DEPARTMENT   OF   COMMERCE 


CIRCULAR 

OP  THE 

BUREAU  OF  STANDARDS 

S.  W.  STRATTON,  DIRECTOR 

No.  43 

JEWELERS'  AND  SILVERSMITHS' 
WEIGHTS  AND  MEASURES 

(2d  Edition) 

A  revised  and  enlarged  edition  of  Bureau  of  Standards 

Circular  No.  43  (1st  edition),  issued  November  1,  1913 

entitled  "The  Metric  Carat" 


JANUARY  24,  1921 


PRICE,  10  CENTS 

Sold  only  by  the  Superintendent  of  Documents,  Government  Printing  Office 
Washington,  D.  C. 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1921 


DEPARTMENT    OF   COMMERCE 


CIRCULAR 

OF  THE 

BUREAU  OF  STANDARDS 

S.  W.  STRATTON.  DIRECTOR 


No.  43 

JEWELERS'  AND  SILVERSMITHS' 
WEIGHTS  AND  MEASURES 

(2d  Edition) 

A  revised  and  enlarged  edition  of  Bureau  of  Standards 

Circular  No.  43  (1st  edition),  issued  November  1,  1913 

entitled  "The  Metric  Carat" 


JANUARY  24,  1921 


PRICE,  10  CENTS 

Sold  only  by  the  Superintendent  of  Documents,  Government  Printing  Office 
Washington,  D.  C. 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1921 


JEWELERS'  AND  SILVERSMITHS'  WEIGHTS  AND 
MEASURES 1 


CONTENTS 

Page 

I.  Introduction 6 

1.  Adoption  of  the  new  metric  carat 6 

2.  Proposed  adoption  of  the  metric  system 6 

II.  The  metric  system 7 

i.  Description 7 

(a)  Legal  status * 7 

(6)  General  outline 7 

(c)  Fundamental  relationships 9 

(d)  Spelling  and  abbreviations  of  units 10 

(e)  Special  ways  to  use  the  tables 10 

a.  Definitions  of  units 1 1 

(a)  Length n 

(b)  Area n 

(c)  Volume 12 

(d)  Capacity 13 

(e)  Mass 14 

3.  Length  conversion  tables 15 

Table  i.— Inches  into  millimeters  (values,  i  to  9;  see  also 

Table  6,  p.  16);  millimeters  into  inches  (values,  i  to  9; 

see  also  Table  7,  p.  18) 15 

Table  2. — Inches  into  centimeters;  centimeters  into  inches. .  15 

Table  3. — Feet  into  meters;  meters  into  feet 15 

Table  4. — Yards  into  meters;  meters  into  yards 15 

Table  5. — Decimal  and  metric  equivalents  of  common 

(binary)  fractions  of  an  inch 15 

Table  6. — Inches  into  millimeters  (values,  o.ooo  to  0.999, 

and  i  to  20;  see  also  Table  i,  p.  15) 16 

Table  7. — Millimeters  into  inches  (values,  o.oo  to  9.99;  see 

also  Table  i,  p.  15) 18 

4.  Tab1es  of  area 20 

Table  8. — Square  inches  into  square  centimeters;  square 

centimeters  into  square  inches 20 

Table  9. — Square  feet  into  square  meters;  square  meters 

into  square  feet 20 

Table  10. — Square  yards  into  square  meters;  square  meters 

into  square  yards 20 

5.  Tables  of  volume 20 

Table  n. — Cubic  inches  into  cubic  centimeters;  cubic 

centimeters  into  cubic  inches 20 

Table  12. — Cubic  feet  into  cubic  meters;  cubic  meters  into 

cubic  feet 20 

Table  13. — Cubic  yards  into  cubic  meters;  cubic  meters  into 

cubic  yards 20 

Table  14. — Cubic  inches  into  liters;  liters  into  cubic  inches. .  20 

Table  15. — Cubic  feet  into  liters;  liters  into  cubic  feet 20 

1  Prepared  by  A.  F.  Beal,  Associate  Physicist,  Bureau  of  Standards. 


Circular  of  the  Bureau  of  Standards 

II.  The  Metric  System — Continued.  Page 

6.  Tables  of  capacity 21 

Table  16. — Minims  into  milliliters;  milliliters  into  minims.  .         21 
Table  17. — U.  S.  fluid  drams  into  milliliters;  milliliters  into 

U.  S.  fluid  drams 21 

Table  18. — Fractions  of  fluid  drams  and  fluid  ounces  into    . 

milliliters 21 

Table  19. — U.  S.  fluid  ounces  into  milliliters 21 

Table  20. — Milliliters  into  U.  S.  fluid  ounces 21 

Table  21. — U.  S.  liquid  pints  into  liters;  liters  into  U.  S. 

liquid  pints 21 

Table  22.— U.  S.  liquid  quarts  into  liters;  liters  into  U.  S. 

•  liquid  quarts 21 

Table  23. — U.  S.  gallons  into  liters;  liters  into  U.  S.  gallons.  .         21 
Table   24. — British  Impeial  gallons  into  liters;  liters  iinto 

British  Imperial  gallons 21 

Table    25. — U.    S.    gallons   into    British    Imperial    gallons; 

British  Imperial  gallons  into  U.  S.  gallons 21 

7.  Tables  of  mass  (weight) 22 

Table  26. — Grains     into  grams  (values,  i  to  9;  see  also  Table 

32,  p.  23);  grams  into  grains  (values,  i  to  9;  see  also  Table 

33.P-23) 22 

Table  27. — Pennyweights  into  grams  (values,  i  to  9;  see  also 

Table  34,  p.  24);  grams  into  pennyweights  (values,  i  to  9; 

see  also  Table  35,  p.  24) 22 

Table  28. — Troy  ounces  into  grams  (values,  i  to  9;  see  also 

Table  36,  p.  25);  grams  into  troy  ounces  (values,  i  to  9; 

see  also  Table  37.  p.  25) 22 

Table  29. — Avoirdupois  ounces  into  grams 22 

Table  30. — Avoirdupois  pounds  into  kilograms  (values,  i  to 

9;  see  also  Table  38,  p.  26);  kilograms  into  avoirdupois 

pounds  (values,  i  to  9;  see  also  Table  39,  p.  26) 22 

Table  31. — Short  tons  into  metric  tons;  metric  tons  into 

short  tons 22 

Table  32. — Grains  into  grams  (values,  o  to  too) 23 

Table  33. — Grams  into  grains  (values,  o  to  100) 23 

Table  34. — Pennyweights  into  grams  (values,  o.oo  to  i.oo; 

also  o  to  too) 24 

Table  35. — Grams  into  pennyweights  (values,  o  to  100) 24 

Table  36. — Troy  ounces  into  grams  (values,  o.oo  to  i.oo;  also 

o  to  100) 25 

Table  37. — Grams  into  troy  ounces  (values,  o  to  100) 25 

Table  38. — Avoirdupois  pounds  into  kilograms  (values,  o  to 

100) 26 

Table  39. — Kilograms  into  avoirdupois  pounds  (values,  o  to 

100) 26 

III.  The  metric  carat 27 

1.  Definition 27 

2.  Conversion  tables 27 

Table  40.— Fractions  of  old  carat  into  new  metric  carat 28 

Table  41  .—Old  carats  into  new  metric  carats 29 


Jewelers'  Weights  and  Measures  5 

Page 

IV.  Gages  (wire  and  drill) 29 

i.  Existing  practice  in  gaging  materials 29 

a.  Wire  gages 30 

(a)  American  wire  gage 30 

(6)  Steel  wire  gage 30 

(c)  Stubs'  steel  wire  gage 30 

(d)  Birmingham  wire  gage 31 

(e)  Standard  wire  gage 31 

(/)  Old  English  or  London  gage 31 

3.  Twist  drill  and  steel  wire  gages 31 

4.  Tables  of  gage  sizes  (inches  and  millimeters) 32 

Table  42. — Douzieme  caliper 32 

Table  43 . — Tabular  comparison  of  wire  gages 33 

Table  44. — Equivalents  of  lettered  sizes,  for  drills  and  Stubs' 

steel  wire  gage 34 

Table  45. — Numbered  sizes,  i  to  60,  for  drills  and  Stubs' 

steel  wire  gage 34 

Table  46. — Numbered  sizes,  60  to  80,  for  drills  and  Stubs' 

steel  wire  gage 35 

Table  47. — Index  to  numbered  sizes,  60  to  80,  drills,  etc. ...  35 

V.  Watch  glasses 35 

1 .  Gage  sizes  for  watch  glasses 35 

2.  Reasons  for  adoption  of  metric  gage  sizes 36 

3 .  Specimen  labels 36 

4.  Influence  of  watchcase  design 37 

5.  Conversion  tables 37 

Table  48.— Diameter  of  watch  glasses;  conversion  of  Lignes 

(i6ths)  into  tenth-millimeters 37 

Table  49. — Height  of  watch  glasses 37 

VI.  Sizes  of  watches 38 

Table  50.— Watch  sizes 38 

VII.  Ring  sizes 39 

1.  Original  standard 39 

2.  Introduction  of  errors 39 

3.  Many  similar  standards 39 

4.  Confusion  also  in  use  of  gage 40 

5.  Outline  of  the  problem 40 

VIII.  Miscellaneous  tables 41 

Table  51. — Decimal  equivalents  of  gold  karats 41 

Table  52 . — Densities  of  various  metals 41 

Table  53. — Melting  points  of  various  metals 41 

Table  54. — Conversion  of  centigrade  temperatures  (C)  into  Fahren- 
heit temperatures  (F) 42 

Table  55. — Conversion  of  Fahrenheit  temperatures  (F)  into  centi- 
grade temperatures  (C) 42 

i.  Approximate  temperatures  by  color 43 

Index 45 


6  Circular  of  the  Bureau  of  Standards 

I.  INTRODUCTION 
1.  ADOPTION  OF  THE  NEW  METRIC  CARAT 

The  carat  weights  in  use  previous  to  July  i,  1913,  in  different 
countries  had  differed  greatly,  scarcely  any  two  of  the  important 
countries  having  the  same  standard.  Even  within  the  United 
States  there  was  not  agreement  in  the  standard  used,  the  various 
makers  of  weights  using  slightly  different  standards.  This  led  to 
considerable  confusion  in  the  weighing  of  gems,  and  was  the 
more  serious  because  of  the  great  value  of  the  article. 

Beginning  July  i,  1913,  the  international  metric  carat  of  200 
milligrams  as  the  unit  of  weight  for  diamonds  and  other  precious 
stones  was  put  into  commercial  use  in  the  United  States  by  practi- 
cally all  the  dealers  in  gems  and  precious  stones  through  the  efforts 
of  a  committee  representing  all  the  principal  firms  handling  gems. 
On  the  same  date  the  Treasury  Department  of  the  United  States 
Government  also  began  the  use  of  this  unit  in  the  customs  service 
for  the  levying  of  import  duties  on  precious  stones,  and  the 
Bureau  of  Standards  recognized  this  unit  for  purposes  of  certifi- 
cation of  all  carat  weights  submitted  to  the  Bureau  for  test. 

The  movement  for  the  adoption  of  a  uniform,  decimally  divided 
standard  was  a  decided  step  forward  and  therefore  has  met  writh 
success.  The  new  metric  carat  of  200  milligrams  is  universally  used 
in  the  United  States  and  has  been  officially  adopted  by  Belgium, 
Bulgaria,  Denmark,  England,  France,  Germany,  Holland,  Italy, 
Japan,  Norway,  Portugal,  Roumania,  Spain,  Sweden,  and  Switzer- 
land. The  Bureau  of  Standards  in  1913  prepared  tables  for  con- 
verting "old"  carats  to  new  metric  carats,  and  vice  versa,  and 
published  them  as  Circular  No.  43.  These  tables  were  of  great  aid 
at  the  time  to  the  transition  from  the  old  unit  of  about  205.3  **&- 
ligrams  and  binary  fractions  to  the  new  unit  and  decimal  fractions. 
2.  PROPOSED  ADOPTION  OF  THE  METRIC  SYSTEM 

The  inconvenience  and  inefficient  use  of  the  present  system  of 
pennyweights  and  grains  as  opposed  to  the  benefits  derived  from 
the  use  of  the  new  metric  decimally  divided  carat  has  become  so 
pronounced  that  the  Bureau  was  invited  to  prepare  a  practical 
working  outline  of  the  metric  system  that  would  suit  the  needs  of 
the  jewelry  trade  and  allied  industries.  The  purpose  of  this  is  to 
make  it  easily  possible  for  jewelers  and  silversmiths  to  substitute 
the  gram  for  the  dual  unit  of  pennyweights  and  grains  2  and  also 
to  use  the  metric  system  in  all  of  their  work. 

a  It  is  desirable  to  note  in  this  connection  that  all  medical  prescriptions  of  the  U.  S.  Army  must  be 
expressed  in  metric  units,  not  in  grains. 


Jewelers'  Weights  and  Measures 


The  Bureau  therefore  is  publishing  this  circular  giving  tables 
of  the  relations  between  the  customary  units  and  the  correspond- 
ing ones  of  the  metric  system.  There  is  also  given  information 
that  is  of  interest  to  other  branches  of  the  jewelry  trade,  such  as 
the  comparative  table  for  the  diameters  corresponding  to  the 
sizes  of  watches. 

With  this  edition,  the  material  on  the  metric  carat  has  been 
revised,  and,  because  of  the  large  amount  of  new  material  which 
has  been  added  to  the  publication,  the  title  has  been  changed. 

II.  THE  METRIC  SYSTEM 
1.  DESCRIPTION 

(a)  LEGAL  STATUS 

The  metric  system  was  rendered  legal  for  all  transactions  in 
the  United  States  by  an  act  of  Congress,  approved  July  28,  1866, 
and  is  now  legal  or  obligatory  in  all  commercial  countries.  Many 
industries  in  the  United  States  are  using  it.  In  Europe,  and  also 
in  many  other  parts  of  the  world,  more  measurements  are  made  in 
metric  terms  than  in  any  other  system.  The  metric  system  must 
be  understood  by  those  who  deal  intelligently  with  their  customers 
in  the  metric  countries. 

(b)  GENERAL  OUTLINE 

The  meter  for  measuring  length,  the  liter  for  measuring  capacity, 
and  the  gram  for  weight  form  the  basis  of  the  metric  system. 
These  units,  together  with  the  multiples  and  subdivisions  given  in 
the  following  table,3  are  sufficient  for  practical  purposes  and  are 
recognized  in  all  countries. 


Correct  English  spelling 

Standard  abbre- 
viations 

10  millimeters=  1  centimeter  

10  mm=  1  cm 

Length  

100  centimeters^  1  meter  
1000  meters        —  1  kilometer 

100cm  =lm 
1000m    -1km 

Capacity.... 
Weight  

1000  milliliters    =  1  liter  
1000  milligrams  =  1  gram  
1000  grams            =1  kilogram 

1000ml  =11 
1000  mg  =lg 
1000  g      =lkg 

1000  kilograms   =  1  metric  ton  

1000kg   =lt 

*  Additional  units,  multiples,  and  subdivisions,  which  may  be  needed  occasionally,  are  given  later  under 
'Definitions  of  Units,"  pp.  n  to  14. 
Tables  giving  the  interrelation  of  units  of  measurement  may  be  found  in  Bureau  Circular  No.  47. 


oo E 


CD  =  — 


10 


3 


tfd 

w 

EH 

W 

grH 

H 

£ 

H 

UQ 


Circular  of  the  Bureau  of  Standards 

Complete  metric  tables  are  formed  by 
combining  the  words  "  METER,"  "  LITER," 
and  "GRAM"  with  the  six  numerical  pre- 
fixes as  in  the  following  tables  : 


IO 


03 


'j      | 


S   1 

fr       C. 


Prefixes 


Meaning 


mill!-    =  one-thousandth 
centi-   =  one-hundredth 

dCCi-       =   one-tenth 

Unit    -one 
deka-    -  ten 


~1O~ 


.01 
ml 


kilo-       =  one  thousand 


"meter"  fa 

length 


"liter"  for  ca- 


/or 


The  metric  unit  of  length  for  jewelers 
and  silversmiths  is  the  millimeter,  or 
one-thousandth  of  a  meter;  the  milli- 
meter is  the  size  of  the  smallest  space 
shown  in  Fig.  i .  It  is  also  very  nearly 
the  diameter  of  a  No.  18  wire  of  American 
(Brown  &  Sharpe)  wire  gage.  For  very 
small  values  of  length,  such  as  the  thick- 
ness of  the  plating  on  an  electroplated 
article,  it  is  convenient  to  use  the 
"  micron,  "  which  is  one-thousandth  of  a 
millimeter.  The  smallest  subdivision  on 
the  head  of  a  micrometer  with  a  milli- 
meter screw  usually  is  o.oi  millimeter, 
or  10  microns.  In  working  material  to 
a  given  dimension  within  a  quarter  of  a 
thousandth  of  an  inch,  the  accuracy  ob- 
tained is  6  microns.  An  inch  equals 
almost  exactly  25.4  millimeters. 

The  liter  is  the  standard  unit  of  capac- 
ity and  is  divided  into  a  thousand  equal 
parts  called  milliliters.  For  ordinary 
purposes,  the  liter 4  is  equivalent  to  a 


4  There  is  a  minute  distinction  between  the  liter  and  1000  cubic  centimeters  which  is  used  only  in  work 
of  extreme  precision.    See  "  Fundamental  Relationship,"  page  9 . 


Jewelers'  Weights  and  Measures  9 

cubic  measure  10  centimeters  on  each  edge,  or  1000  cubic  centi- 
meters. A  liter  is  a  trifle  larger  than  a  U.  S.  liquid  quart. 

The  gram  is  the  unit  of  mass  (or  weight) ;  1000  grams  make  a 
kilogram.  The  kilogram  is  exactly  the  mass  of  a  liter  of  water 
when  at  the  temperature  of  4°  C  (39.2°  F).  The  gram  is  fre- 
quently subdivided  into  1000  parts  called  milligrams.  For  a 
small  article  (less  than  i  gram)  the  weight  usually  is  expressed  in 
milligrams.  A  piece  of  platinum  wire  one-half  inch  long  and 
American  (B.  &  S.)  wire  gage  No.  30  weighs  about  14  milligrams;  if 
of  copper  wire  it  weighs  about  6  milligrams.  A  one-half  carat  dia- 
mond weighs  exactly  100  milligrams.  For  large  weighings,  or 
in  expressing  the  sum  of  several  weighings,  it  is  convenient  to 
use  the  gram  even  up  to  about  10  ooo  grams,  or  10  kilograms, 
thus  avoiding  the  change  from  one  unit  to  another.  In  the 
metric  system  a  quantity  is  always  expressed  in  terms  of  only 
one  unit.  The  gram  equals  about  15.4  grains,  and  the  kilogram  is 
about  2.2  avoirdupois  pounds. 

A  change  to  a  larger  or  smaller  metric  measure  of  length, 
area,  volume,  capacity,  or  weight  is  effected  by  merely  multi- 
plying or  dividing  by  10  or  a  multiple  of  10.  This  enables  those 
who  use  the  metric  system  to  make  accurate  mental  and  written 
calculations  with  a  rapidity  which  would  otherwise  be  impossible. 

(c)  FUNDAMENTAL  RELATIONSHIPS 

The  tables  in  this  circular  have  been  prepared  to  aid  in  changing 
values  from  one  system  of  weights  and  measures  to  another. 
The  U.  S.  units  are  referred  to  except  when  otherwise  indicated. 
The  tables  have  been  based  upon  the  following  equivalents: 

39.37  United  States  inches  =i  meter 

i  United  States  gallon  =231  cubic  inches 

i  liter  =1000.027  cubic  centimeters 

i  United  States  avoirdupois  pound=o. 4535924277  kilogram 

The  values  in  most  of  the  tables  have  been  expressed  with  the 
accuracy  usually  required  at  the  bench.  In  some  cases,  however, 
many  figures  are  given  for  use  in  connection  with  precise  work. 
Equivalents,  such  as  those  in  the  tables  given  on  pages  15,  20,  21, 
and  22,  should  be  used  only  to  the  required  degree  of  accuracy. 
For  example,  in  Table  2,  page  15,  it  is  stated  that  4  inches  are 
equal  to  10.16002  centimeters.  This  may  be  rounded  off,  giving 
4  inches  equal  to  10.2  centimeters,  or,  if  less  accuracy  is  desired, 
the  approximate  value  of  10  centimeters  may  be  used. 

16340°— 21 2 


io  Circular  of  the  Bureau  of  Standards 

(d)  SPELLING  AND  ABBREVIATION  OF  UNITS 

The  spelling  of  the  names  of  metric  units  is  that  given  in  the 
law  of  July  28,  1866,  legalizing  the  metric  system  in  the  United 
States. 

The  following  principles  of  abbreviation  have  been  adopted 
by  the  Bureau  in  conformity  with  international  agreement. 

1.  The  period  is  omitted  after  the  abbreviations  of  the  metric 
units,  while  it  is  used  after  those  of  the  customary  system. 

2.  The  same  abbreviation  is  used  for  both  singular  and  plural. 

3.  Unless  all  of  the  text  is  printed  in  capital  letters,  only  small 
letters  are  used  for  abbreviations  (except  in  the  case  of  A.  for 
acre,  where  the  use  of  the  capital  letter  is  general) . 

4.  The  exponents  "2"  and  "3"  following  abbreviations  of  units 
of  length,  are    used    to  signify  area  and  volume,  respectively, 
in  the  case  of  the  metric  units  instead  of  the  longer  prefixes  "  sq.  " 
and  "cu. "     In  conformity  with  this  principle  the  abbreviation 
for  cubic  centimeter  is  "cm3"  in  preference  to  any  other  usual 
practice. 

(e)  SPECIAL  WAYS  TO  USE  THE  TABLES 

When  the  tables  do  not  give  the  equivalent  of  any  desired 
quantity  directly  and  completely,  the  equivalent  can  usually 
be  obtained  without  the  necessity  of  making  a  multiplication. 
This  is  done  by  using  quantities  from  different  parts  of  the  same 
table  or  from  several  tables,  making  a  shift  of  decimal  points  if 
necessary,  and  merely  adding  the  results.  For  example: 

1.  Convert  27.3  millimeters  into  inches.     (Refer  to  Table  i, 
P-  I5-) 

2  mm=o. 07874  inch,  hence  20.0  mm=o.  7874    inch 

7.omm=  .  27559  inch 

3  mm=  .11811  inch,  hence      .3  mm=  .01181  inch 

27.3  mm=i.  0748  inches 

2.  Convert  1.0748  inches  into  millimeters.     (Refer  to  Table  i, 
P-  15.) 

i  inch  =25-  4°°  mm 

7  inches=i77.  8  mm,  hence  o.  07      inch  =   i.  778  mm 
4  inches=ioi.  6  mm,  hence    .004    inch  =     .  102  mm 

8  inches=203-  2  mm,  hence    .  0008  inch  =     .  020  mm 

i.  0748  inches=27.  300  mm 

3.  Convert  253  pennyweights  13.5  grains  into  grams. 

200  pennyweights  (Table  34,  p.  24)  =311.  035  g 

53  pennyweights  (Table  34,  p.  24)  =  82.  424  g 

13  grains  (Table  32,  p.  23)  =      .  842  g 

5  grains=o.324  g,  hence  0.5  grain  =       .  032  g 

253  pennyweights  13.5  grains  =  394.  333  g 


Jewelers'  Weights  and  Measures  1 1 

2.  DEFINITIONS  OF  UNITS 

(a)  LENGTH 

Fundamental  Units 

A  METER  (m)  is  a  unit  of  length  equivalent  to  the  distance 
between  the  defining  lines  on  the  international  proto- 
type meter  at  the  International  Bureau  of  Weights 
and  Measures  when  this  standard  is  at  the  temperature 
of  melting  ice  (o°  C). 

A  YARD  (yd.)  is  a  unit  of  length  equivalent  to  $$4$  of  a 
meter. 

Multiples  and  Submultiples 

i  kilometer  (km)  =  1000  meters. 

i  hectometer  (hm)  =  100  meters. 

i  dekameter  (dkm)  =  10  meters. 

i  decimeter  (dm)  =0.1  meter. 

i  centimeter  (cm)  =0.01  meter. 

i  millimeter  (mm)  =0.001  meter  =  0.1  centimeter. 

i  micron  (M)  =0.000001  meter  =  0.001  millimeter. 

i  millimicron  (m/x)  =0.000000001  meter  =0.00 1  micron. 

i  foot  (ft.)  -=K  yard=if^  meter. 

i  inch  (in.)  =&  yard  =  -rV  foot  =  -sVW  meter. 

i  link  (li.)  =0.22  yard  =  7. 92  inches. 

i  rod  (rd.)  =5^2  yards =  i6l/2  feet. 

i  chain  (ch.)  =22  yards  =  100  links  =  66  feet  =  4  rods. 

i  furlong  (fur.)  =  220  yards  =  40  rods  =  10  chains. 

i  statute  mile  (mi.)  =  1 760  yards  =  5280  feet  =  320  rods. 

i  hand  =  4  inches. 

i  point  (printers')  =  -fa  inch  (approximately) . 

i  point  (silversmiths')  =TiiW  inch. 

i  mil=o.ooi  inch. 

i  fathom  =  6  feet. 

i  span  =  9  inches  =  yi  fathom. 

i  nautical  mile 

United  States  =  6080. 20  feet  =  1.151 553 

statute  miles  =  1853.2 49  meters, 
i  geographical  mile 

(b)  AREA 

Fundamental  Units 

A  SQUARE  METER  (m2)  is  a  unit  of  area  equivalent  to  the 
area  of  a  square  the  sides  of  which  are  i  meter. 

A  SQUARE  YARD  (sq.  yd.)  is  a  unit  of  area  equivalent  to  the 
area  of  a  square  the  sides  of  which  are  i  yard. 


12  Circular  of  the  Bureau  of  Standards 

Multiples  and  Submultiples 

i  square  kilometer  (km2)  =  i  ooo  ooo  square  meters. 

i  hectare  (ha),  or  square  hectometer  (hm2)  =  10  ooo  square 

meters. 

i  are  (a),  or  square  dekameter  (dkm2)  =  100  square  meters, 
i  Centare  (ca)  =  i  square  meter. 
i  square  decimeter  (dm2)  =0.01  square  meter, 
i  square  centimeter  (cm2)  =0.0001  square  meter. 
i  square  millimeter  (mm2)  =0.000001   square  meter =0.01 

square  centimeter. 

i  square  foot  (sq.  ft.)  =£  square  yard. 

i  square  inch  (sq.  in.)  =TTFF  square  yard  =  -rir  square  foot, 
i  square  link  (sq.  li.)  =0.0484  square  yard  =  62. 7264  square 

inches, 
i  square  rod  (sq.  rd.)  =30.25  square  yards  =  272. 25  square 

feet  =  62 5  square  links. 
i    square   chain  (sq.  ch.)  =484    square   yards  =  16   square 

rods  =  100  ooo  square  links, 
i    acre    (A.)  =4840    square  yards  =  1 60    square    rods  =  io 

square  chains, 
i  square  mile  (sq.  mi.)  =3  097  600  square  yards  =  640  acres. 

(c)  VOLUME 

Fundamental  Units 

A  CUBIC  METER  (m3)  is  a  unit  of  volume  equivalent  to  a 

cube  the  edges  of  which  are  i  meter. 
A  CUBIC  YARD  (cu.  yd.)  is  a  unit  of  volume  equivalent  to  a 
cube  the  edges  of  which  are  i  yard. 

Multiples  and  Submultiples 

i  cubic  kilometer  (km3)  =  i  ooo  ooo  ooo  cubic  meters. 

i  cubic  hectometer  (hm3)  =  i  ooo  ooo  cubic  meters. 

i  cubic  dekameter  (dkm3)  =  1000  cubic  meters. 

i  stere  (s)  =  i  cubic  meter. 

i  cubic  decimeter  (dm3)  =0.001  cubic  meter. 

i    cubic   centimeter    (cm3)  =0.000001    cubic   meter  =  0.00 1 

cubic  decimeter, 
i  cubic  millimeter  (mm3)  =0.000000001  cubic  meter  =  o.ooi 

cubic  centimeter. 

i  cubic  foot  (cu.  ft.)  =TT  cubic  yard, 
i  cubic  inch  (cu.  in.)  =  46656  cubic  yard  =  T^  cubic  foot, 
i  board  foot  =  144  cubic  inches  =  -rV  cubic  foot, 
i  cord  (cd.)  =128  cubic  feet. 


Jewelers'  Weights  and  Measures  13 

(d)  CAPACITY 

Fundamental  Units 

A  LITER  (1)  is  a  unit  of  capacity  equivalent  to  the  volume 
occupied  by  the  mass  of  i  kilogram  of  pure  water  at  its 
maximum  density  (at  a  temperature  of  4°  C,  prac- 
tically) and  under  the  standard  atmospheric  pressure 
(of  760  mm).  It  is  equivalent  in  volume  to  1.000027 
cubic  decimeters. 

A  GALLON  (gal.)  is  a  unit  of  capacity  equivalent  to  the  vol- 
ume of  231  cubic  inches.  It  is  used  for  the  measure- 
ment of  liquid  commodities  only. 

A  BUSHEL  (bu.)  is  a  unit  of  capacity  equivalent  to  the 
volume  of  2150.42  cubic  inches.  It  is  used  in  the 
measurement  of  dry  commodities  only.5 

Multiples  and  Submultiples 

i  hectoliter  (hi)  =  i  oo  liters. 

i  dekaliter  (dkl)  =  10  liters. 

i  deciliter  (dl)  =0.1  liter. 

i  centiliter  (cl)  =0.01  liter. 

i  milliliter  (ml)  =0.001  liter  =  1.000027  cubic  centimeters. 

i  liquid  quart  (liq.  qt.)  =>^  gallon  =  5 7. 75  cubic  inches. 

i  liquid  pint  (liq.  pt.)  =>i  gallon  =  K  liquid  quart  =  2 8. 8 75 
cubic  inches. 

i  gill  (gi.)  =  -fa  gallon  =  K  liquid  pint  =  7.21 875  cubic  inches. 

i  fluid  ounce  (fl.  oz.)  =TTF  gallon  =  ^  liquid  pint. 

i  fluid  dram  (fl.  dr.)  =y&  fluid  ounce  =  T^r  liquid  pint. 

i  minim  (min.  or  ^l)  =-£$  fluid  dram  =  TSTF  fluid  ounce. 

i  firkin  =  9  gallons. 

i  peck  (pk.)  =%  bushel  =  53 7. 605  cubic  inches. 

i  dry  quart  (dry  qt.)  =  -fa  bushel  =l/i  peck  =  6 7. 20062 5 
cubic  inches. 

i  dry  pint  (dry  pt.)  =  -fa  bushel  =  %  dry  quart  =  33.6003 1 25 
cubic  inches. 

i  barrel  (for  fruit,  vegetables,  and  other  dry  commodi- 
ties)6 =705  6  cubic  inches  =  105  dry  quarts. 

6  The  above  bushel  is  the  so-called  stricken  or  struck  bushel.  Many  dry  commodities  are  sold  by  heaped 
bushel,  which  is  generally  specified  in  the  State  laws  to  be  the  usual  stricken  bushel  measure  "duly  heaped 
in  the  form  of  a  cone  as  high  as  the  article  will  admit "  or  ''  heaped  as  high  as  may  be  without  special  effort 
or  design. "  The  heaped  bushel  was  originally  intended  to  be  25  per  cent  greater  than  the  stricken  bushel. 

'  As  fixed  by  United  States  statute,  approved  Mar.  4,  1915- 


14  Circular  of  the  Bureau  of  Standards 

(e)  MASS 

Fundamental  Units 

A  KILOGRAM  (kg)  is  a  unit  of  mass  equivalent  to  the  mass 
of  the  international  prototype  kilogram  at  the  Interna- 
tional Bureau  of  Weights  and  Measures. 

An  AVOIRDUPOIS  POUND  (lb.  av.)  is  a  unit  of  mass  equivalent 
to  0.4535924277  kilogram. 

A  GRAM  (g)  is  a  unit  of  mass  equivalent  to  one-thousandth 
of  the  mass  of  the  international  prototype  kilogram  at 
the  International  Bureau  of  Weights  and  Measures. 

A  TROY  POUND  (lb.  t.)  is  a  unit  of  mass  equivalent  to  %i%%  of 
that  of  the  avoirdupois  pound. 

Multiples  and  Submultiples 

i  metric  ton  (t)  =  1000  kilograms. 

i  hectogram  (hg)  =100  grams  =0.1  kilogram. 

i  dekagram  (dkg)  =10  grams  =  0.01  kilogram. 

i  decigram  (dg)  =0.1  gram. 

i  centigram  (eg)  =0.01  gram. 

i  milligram  (mg)  =0.001  gram. 

i  avoirdupois  ounce  (oz.  av.)  =  -rV  avoirdupois  pound. 

i  avoirdupois  dram  (dr.  av.)  =-zir  avoirdupois  pound  = 
iV  avoirdupois  ounce. 

i  grain  (gr.)=T^nr  avoirdupois  pound  =  i$fc  avoirdupois 
ounce  = -5-7*5-0-  troy  pound. 

i  apothecaries'  pound  (lb.  ap.)  =  i  troy  pound  =TOTT  avoir- 
dupois pound. 

i  apothecaries'  or  troy  ounce  (oz.  ap.,  or  3,  or  oz.  t.)  =iV 
troy  pound  =  74o8o°o  avoirdupois  pound  =  480  grains. 

i  apothecaries'  dram  (dr.  ap.  or  5)  =  TS  apothecaries'  pound  = 
]/%  apothecaries'  ounce  =  60  grains. 

i  pennyweight  (dwt.)  =-fa  troy  ounce  =  24  grains. 

i  apothecaries'  scruple  (s.  ap.  or  9)=X  apothecaries' 
dram  =  20  grains. 

i  metric  carat  (c)  =200  milligrams  =  0.2  gram. 

i  short  hundredweight  (sh.  cwt.)  =  100  avoirdupois  pounds. 

i  long  hundredweight  (1.  cwt.)  =112  avoirdupois  pounds. 

i  short  ton  =  2000  avoirdupois  pounds. 

i  long  ton  =  2240  avoirdupois  pounds. 


Jewelers1  Weights  and  Measures 
3.  LENGTH  CONVERSION  TABLES 


•LABILE/  1 

LABLE,  Z 

lA.t5.Ut,  J           1AJD.L.&  4 

*«*-  JSS. 

**~  SS£ 

Feet   Meters 

Yards    Meters 

1  =  25.4001 
2  -  50.8001 
3  =  76.2002 
4  =101.6002 

1  =  2.54001 
3  =  5.08001 
3  =  7.62002 
4  =10.16002 

1  =0.304801 
2  =  .609601 
3  =  .914402 
4  =1.219202 

1  =0.914402 
2  =1.  828804 
3  =2.743205 
4  =3.657607 

5  =127.0003 
0  =152.4003 
7  =177.8004 
8  =203.2004. 
9  =228.6005 

5  =12.70003 
6  =15.24003 
7  =17.78004 
8'  =20.32004 
9  =22.86005 

5  =1.524003 
6  =1.  828804 
7  =2.133604 
8  =2.438405 
9  =2.743205 

5  =4.572009   • 
6  =5.486411 
7  =6.400813 
8  =7.315215 
9  =8.229616 

0.  03937=  1 
.  07874=  2 
.  11811=  3 
.  15748=  4 

0.  3937=  1 
.  7874=  2 
1.  1811=  3 
1.  5748=  4 

3.  28083=  1 
6.  56167=  2 
9.  84250=  3 
13.  12333=  4 

1.  093611=  1 
2.  187222=  2 
3.  280833=  3 
4.  374444=  4 

.  19685=  5 
.  23622=  6 
.  27559=  7 
.  31496=  8 
.  35433=  9 

1.  9685=  5 
2.  3622=  6 
2.  7559=  7 
3.  1496=  8 
3.  5433=  9 

16.  40417=  5 
19.  68500=  6 
22.  96583=  7 
26.  24667=  8 
29.  52750=  9 

5.  468056=  5 
6.  561667=  6 
7.  655278=  7 
8.  748889=  8 
9.  842500=  9 

a  See  also  extended  Tables  6  and  7. 

TABLE  5. — Decimal  and  Metric  Equivalents  of  Common  (Binary)  Fractions  of  an 

Inch 


Fraction's  of  inch 

Equivalent  in 
millimeters 

Fractions  of  inch 

Equivalent  in 
millimeters 

Eighths  and 
quarters 

Decimal 

Sixty-fourths 

Decimal 

y* 

0.125 

3.175 

1 

0.  015625 

0.397 

.250 

6.350 

3 

.  046875 

1.191 

^ 

.375 

9.525 

5 

.  078125 

1.984 

% 

.500 

12.700 

7 

.  109375 

2.778 

9 

.  140625 

3.572 

y* 

.625 

15.  875 

y* 

.750 

19.  050 

11 

.  171875 

4.366 

H 

.875 

22.  225 

13 

.  203125 

5.  159 

15 

.  234375 

5  953 

Sixteenths: 

17 
19 

265625 
'.  296875 

6.747 
7.541 

1 
3 
5 
7 

.0625 
.1875 
.3125 
.4375 

1.588 
4.763 
7.938 
11.  113 

21 
23 
25 
27 

.  328125 
.359375 
.390625 

.  421875 

8.334 
9.128 
9.922 
10.  716 

9 

.5625 

14.  288 

29 

.  453125 

11.509 

11 
13 

.6875 
.8125 
.9375 

17.463 
20.638 
23.  813 

31 
33 

35 

.  484375 
.  515625 
.  546875 

12.  303 
13.097 
13.  891 

Thirty-seconds: 

37 
39 

.  578125 
.609375 

14.  684 
15.  478 

1 

.  03125 

.794 

41 

.640625 

16.  272 

3 

.09375 

2.381 

43 

.  671875 

17.066 

5 

.  15625 

3.969 

45 

.  703125 

17.  859 

7 

.  21875 

5.556 

47 

.  734375 

18.  653 

9 

.  28125 

7.144 

49 

.  765625 

19.  447 

11 

.  34375 

8.731 

51 

.  796875 

20.  241 

13 

.40625 

10.  319 

53 

.  828125 

21.034 

15 

.  46875 

11.906 

55 

.859375 

21.  828 

17 

.  53125 

13.494 

57 

.890625 

22.  622 

19 

.  59375 

15.  081 

59 

.  921875 

23.  416 

21 

.  65625 

16.  669 

61 

.  953125 

24.209 

23 

.  71875 

18.  256 

63 

.  984375 

25.003 

25 

.  78125 

19.844 

27 

.84375 

21.431 

29 

.90625 

23.  019 

31 

.  96875 

24.606 

16 

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Jewelers'  Weights  and  Measures 

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SS3SS  SSSSS  gSKKS  SSRSR  SSSS3S 


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Circular  of  the  Bureau  of  Standards 
4.  TABLES  OF  AREA 


TABLE  8 

TABLE  9 

TABLE  10 

?*-»  SS? 

mches     meters 

Square    Square 
feet       meters 

Square    Square 
yards     meters 

1     =  6.452 
2     =12.903 
3    -19.355 
4    =25.807 

1     =0.0929 
2    =  .1858 
3    =  .2787 
4    =  .3716 

1    =0.836 
2    =1.  672 
3    =2.508 
4    =3.345 

5    =32.258 
6    =38.710 
7     =45.161 
8    =51.613 
9     =58.065 

5    =1  .4645 
6    =  .5574 
7     =  .6503 
8    =  .7432 
9    =  .8361 

5    =4.  181 
6    =5.017 
7     =5.853 
8    =6.689 
9    =7.525 

0.1550=     1 
.  3100=     2 
.  4650=     3 
.  6200=     4 

10.  764=     1 
21.  528=     2 
32.  292=     3 
43.  055=     4 

1.  196=     1 
2.  392=     2 
3.  588=     3 
4.  784=     4 

.  7750=     5 
.  9300=     6 
1.  0850=     7 
1.  2400=     8 
1.  3950=     9 

53.  819=     5 
64.  583=     6 
75.  347=     7 
86.  111=     8 
96.  875=     9 

5.  980=     5 
7.  176=     6 
8.372=     7 
9.  568=     8 
10.  764=     9 

5.  TABLES  OF  VOLUME 


TABLE  11 

TABLE  12 

TABLE  13 

TABLE  14 

TABLE  15 

£±cs    2S 

mches       meters 

Cubic        Cubic 
feet         meters 

Cubic        Cubic 
yards        meters 

Cubic        T  u 
inches        Llters 

™iC       Liters 

1     =   16.387 
2    =  32.774 
3    =  49.161 
4    =  65.549 

1     =0.  0283 
2     =  .0566 
3    =  .0850 
4    =  .1133 

1    =0.7646 
2     =1.5291 
3    =2.2937 
4    =3.0582 

1    =0.0164 
2     =  .0328 
3    =  .0492 
4    =  .0655 

1     =  28.316 
2     =  56.633 
3    =  84.949 
4    =113.265 

5    =  81.936 
6    =  98.323 
7    -114.710 
8    -131.097 
9    =147.484 

5    =  .1416 
6    -  .1699 
7     =  .1982 
8    =  .2265 
9    =  .2549 

5    =3.8228 
6    =4.5874 
7     =5.3519 
8    =6.1165 
9    =6.8810 

5     =  .0819 
6    -  .C983 
7     =   .1147 
8    =  .1311 
9     =  .1475 

5    =141.581 
6    =169.898 
7     =198.214 
8    =226.530 
9    =254.846 

0.  0610=     1 
.  1220=     2 
.1831=     3 
.  2441=     4 

35.  314=     1 
70.  629=     2 
105.  943=     3 
141.  258=     4 

1.  3079=     1 
2.  6159=     2 
3.  9238=     3 
5.  2318=     4 

61.  03=     1 
122.  05=     2 
183.  08=     3 
244.  10=     4 

0.  03532=     1 
.  07063=-     2 
.  10595=     3 
.  14126=     4 

.  3051=     5 
.  3661=     6 
.4272=     7 
.  4882=     8 
.  5492-     9 

176.  572=     5 
211.  887=     6 
247.  201-     7 
282.  516-     8 
317.  830=     9 

6.  5397=     5 
7.  8477=     6 
9.  1556=     7 
10.  4635=     8 
11.  7715=     9 

305.  13=     5 
366.  15=     6 
427.  18=     7 
488.  20=     8 
549.  23=     9 

.  17658=     5 
.21189=     6 
.24721=     7 
.28252=     8 
.31784=     9 

Jewelers'  Weights  and  Measures 
6.  TABLES  OF  CAPACITY 


21 


TABLE  16 

TABLE  17 

TABLE  18 

TABLE  19 

TABLE  20 

Min^     ST 

u.  s.     »»,,„ 

££  «* 

U.  S.     U.S.  ,,,,,,, 
fluid     fluid  *?»1H- 
drams  ounce  litc 

flufd          Mffli- 
££•         »ters 

H  ss- 

1    =0.063 
8    =  .123 
3    =  .185 
4    =  .246 

1     =3.70 
3    =7.39 
3    =11.09 
4    =  14.  79 

i^=    ,,1,=  1.85 
1     =    >6=  3.  70 
1^=    A=  5.54 
2    -    J4=  7.39 

1     =  29.57 
3     =  59.15 
3    =88.72 
4    =118.29 

0.  0338=     1 
.  0676=     3 
.  1014=     3 
.  1353=     4 

6    =  .308 
6    =  .370 
7     =  .431 
8    =  .493 
9    =  .554 

5    =  18.  48 
6    =22.18 
7    =25.88 
8    =29.57 
9    =33.27 

314=    A=  9-24 
3    =    H-11.09 

3^=    A-  12.  94 
4    =    >4=14.  79 
4H=    A=16.63 

5    =147.86 
6    =177.44 
7    =207.01 
8    =236.58 
9    =266.16 

.  1691=     5 
.  2029=     6 
.  2367=     7 
.  2705=     8 
.  3043=     9 

16.  23=     1 
32.  46=     » 
48.  69=     3 
64.92=     4 

0.  271=     1 

.541=   a 

.812=     3 
1.  082=     4 

5    =    5^=18.48 
5K=    H=20.33 
6    =    %=22.18 
6J^=    $=24.  03 

1O    =295.73 
11     =325.30 
13     =354.87 
13    =384.45 

.3381=     10 
.  6763=     30 
1.  0144=     3O 
1.  3526=     40 

81.  16=     5 
97.  39=     6 
113.  62=     7 
129.  85=     8 
146.  08=     9 

1.  353=     5 
1.  623=     6 
1.  894=     7 
2.  164=     8 
2.  435=     9 

7     =    ^=25.88 
7H=    #=27.72 
8    =1     =29.57 

14    =414.02 
15    =443.59 
16    =473.17 

1.  6907=     5O 
2.  0289=     60 
2.  3670=     7O 
2.  7052=     8O 
3.  0433=     9O 

TABLE  21 

TABLE  22 

TABLE  23 

TABLE  24 

TABLE  25 

U.S. 
liquid       Liters 
pints 

U.S. 
liquid       Liters 
quarts 

gallon's       Liters 

British 
Imperial     Liters 
gallons 

„  «,           British 
AS.       '^s' 

1     =0.473 
3    =  .946 
3    =1.419 
4    =1.893 

1    =0.946 
8    =1.893 
3    =2.839 
4    =3.785 

1     =  3.785 
8    =  7.571 
3    =11.356 
4    =15.141 

1    =4.546 
3    =9.092 
3    =  13.  638 
4    =18.184 

1     =0.8327 
a    =1.6654 
3    =2.4980 
4    =3.3307 

5    =2.366 
6    =2.839 
7     =3.312 
8    =3.785 
9    =4.258 

5    =4.732 
6    =5.678 
7     =6.624 
8    =7.571 
9    =8.517 

5    =18.927 
6    =22.712 
7     =26.497 
8    =30.  283 
9    =34.068 

5    =22.730 
6    =27.276 
7     =31.  822 
8    =36.368 
9    =40.914 

5    =4.1634 
6    =4.9961 
7    =5.8287 
8    =6  6614 
9    =7.4941 

2.  113=     1 
4.  227=     2 
6.  340=     3 
8.  454=     4 

1.  057=     1 
2.  113=     3 
3.  170=     3      . 
4.  227=     4 

0.  2642=     1 
.  5284=     3 
.  7925=     3 
1.  0567=     4 

0.  2200=     1 
.  4400=     3 
.  6599=     3 
.  8799=     4 

1.  2009=     1 
2.  4019=     a 
3.  6028=     3 
4.8038=     4 

10.  567=     5 
12.  681=     6 
14.  794=     7 
16.  907=     8 
19.  021=     9 

5.  284=     5 
6.  340=     6 
7.  397=     7 
8.  454=     8 
9.  510=     9 

1.  3209=     5 
1.  5851=     6 
1.  8492=     7 
2.  1134=     8 
2.  3776=     9 

1.  0999=     5 
1.  3199=     6 
1.  5398=     7 
1.  7598=     8 
1.  9798=     9 

6.  0047=     5 
7.  2057=     6 
8.  4066=     7 
9.  6075=     8 
10.  8085-     9 

22 


Circular  of  the  Bureau  of  Standards 
7.  TABLES  OF  MASS  (WEIGHT) 


TABLE  26 

TABLE  27 

TABLE  28 

Grains0     Grains  «• 

weK>     Grams" 

ouncLc     Grams  * 

1    =0.06480 
2     =  .12960 
3    =  .  19440 
4    =  .25920 

1    =  1.55517 
2    =  3.11035 
3    =  4.66552 
4    =  6.22070 

1     =  31.10348 
2    =  62.20696 
3    =  93.31044 
4    =124.41392 

5    =  .32399 
6    =  .38879 
7     =  .45359 
8     =  .51839 
9    =  .58319 

5    =   7.77587 
6    =  9.33104 
7     =10.88622 
8    =12.44139 
9    =  13.  99657 

5    =155.51740 
6    =186.62088 
7     =217.72437 
8    =248.82785 
9    =279.93133 

15.  4324=     1 
30.  8647=     3 
46.  2971=     3 
61.  7294=     4 

0.  64301=     1 
1.  28603=     3 
1.  92904=     3 
2.  57206=     4 

0.  03215=     1 
.  06430=     2 
.  09645=     3 
.  12860=     4 

77.  1618=     5 
92.  5941=     6 
108.  0265=     7 
123.  4589=     8 
138.  8912=     9 

3.  21507=     5 
3.  85809=     6 
4.50110=     7 
5.  14412=     8 
5.  78713=     9 

.  16075=     5 
.  19290=     6 
.  22506=     7 
.  25721=     8 
.  28936=     9 

a  See  also  extended  Tables  32  and  33. 
&  See  also  extended  Tables  34  and  35. 
c  See  also  extended  Tables  36  and  37. 


TABLE  29 

TABLE  30 

TABLE  31 

Avoir- 
dupois      Grams 

Avoir- 
dupois Grams 

Avoir- 
dupois Grams 

Avoir- 
dupois Grams 

Avoir-        KUo_n 

Short       Metric 

ounces 

ounces                 ounces 

ounces 

pounds  «  gr< 

4    =113.398  i      8    =226.796 

12    =340.194 

1     =0.45359 

1    =0.90718 

M=     7.  087 

4^=120.485 

81-4=233.884 

12^4=347.282 

2     =  .90718            2     =1.81437 

14=  14.175 

4)4=127.573 

8^=240.971 

12U=354.369 

3    =1.36078 

3    =2.72155 

%=  21.262 

4%=  134.  660 

8%=  248.  058 

12%=  361.  456 

4    =1.81437 

4    =3.62874 

1    =  28.350 

5    =141.748 

9    =255.146 

13    =368.544 

5    =2.26796 

5    =4.53592 

1)4=  35.437 
\Yy=  42.524 

514=  148.  835 
5)4=155.922 

9)4=  262.  233 
9)4=269.321 

13)4=375.631 

6    =2.72155 
7    =3.17515 

6    =5.44311 

7     =6.35029 

194=  49.612 

5%-  163.  010 

9%=  276.  408 

13%=  389!  806 

8    =3.62874 

8    =7.25748 

. 

9    =4.08233 

9    =8.16466 

2    =  56.699 

6    =170.097 

10    =283.495 

14    =396.893 

2J4=  63.  786 

6)4=177.  185 

10)4=290.583 

14)4=403.981      2.20462=     1 

1.  10231=     1 

2)4=  70.874 

6)4=184.272 

10)4=297.670 

14)4=411.068   ;  4.40924=     2 

2.  20462-     8 

2%=  77.961 

6%=  191.  359 

10%=  304.  757 

14%=  418.  156  •'  6.61387=     3 

3.  30693-     3 

8.  81849=     4 

4.  40924-     4 

3    =  85.049 

7    =198.447 

11    =311.845 

15    =425.243 

3%=  92.136 

7)4=205.534 

11)4=318.932 

15)4=432.330 

11.02311=     5 

5.  51156-     5 

3»4=  99.223 
3%=  106.  311 

7%=  219.  709 

11)4=326.020 
11%=  333.  107 

15)4=439.418 
15%=  446.  505 
16'   =453.592 

13.  22773=     6 
15.  43236=     7 
17.  63698=     8 

6.  61387-    6 
7.  71618=     7 
8.  81849-     8 

19.  84160-     9 

9.  92080-     9 

i  See  also  extended  Tables  38  and  39. 


Jewelers'  Weights  and  Measures 
MASS— GRAINS  AND   GRAMS 


23 


TABLE  32 

TABLE  33 

[1  grain=  0.06479892  gram 

[1  gram=  15.4323564  grains] 

Grains 

Grams                   Grains 

Grams 

Grams 

1 
Grains                   Grams 

Grains 

0 

0.000 

55 

3.564 

0 

0.00 

55 

848.  78 

1 

.065 

56 

3.629 

1 

15.43 

56 

864.  21 

2 

.130 

57 

3.694 

2 

30.86 

57 

879.64 

3 

.194 

58 

3.758 

3 

46.30 

58 

895.08 

4 

.259 

59 

3.823 

4 

61.73 

59 

910.  51 

5 

.324 

60 

3.888 

5 

77.16 

60 

925.94 

6 

61 

3.953 

6 

92.59 

61 

941.37 

7 

!454 

62 

4.018 

7 

108.  03 

62 

956.  81 

8 

.518 

63 

4.082 

8 

123.  46 

63 

972.  24 

9 

.583 

64 

4.147 

9 

138.  89 

64 

987.  67 

10 

.648 

65 

4.212 

10 

154.32 

65 

1003.  10 

11 

.713 

66 

4.277 

11 

169.  76 

66 

1018.  54 

12 

.778 

67 

4.342 

12 

185.  19 

67 

1033.  97 

13 

.842 

68 

4.406 

13 

200.62 

68 

1049.  40 

14 

.907 

69 

4.471 

14 

216.05 

69 

1064.83 

15 

.972 

70 

4.536 

15 

231.49 

70 

1080.  26 

16 

1.037 

71 

4.601 

16 

246.  92 

71 

1095.  70 

17 

1.102 

72 

4.666 

17 

262.  35 

72 

1111.  13 

18 

1.166 

73 

4.730 

18 

277.  78 

73 

1126.  56 

19 

1.231 

74 

4.795 

19 

293.21 

74 

1141.  99 

20 

1.296 

75 

4.860 

20 

308.  65 

75 

1157.  43 

21 

1.361 

76 

4.925 

21 

324.  08 

76 

1172.  86 

22 

1.426 

77 

4.990 

22 

339.  51 

77 

1188.29 

23 

1.490 

78 

5.054 

23 

354.94 

78 

1203.  72 

24 

1.555 

79 

5.119 

24 

370.  38 

79 

1219.  16 

25 

1.620 

80 

5.184 

25 

385.  81 

80 

1234.  59 

26 

1.685 

81 

5.249 

26 

401.  24 

81 

1250.  02 

27 

1.750 

82 

5.314 

27 

416.  67 

82 

1265.  45 

28 

1.814 

83 

5.378 

28 

432.  11 

83 

1280.  89 

29 

1.879 

84 

5.443 

29 

447.54 

84 

1296.  32 

30 

1.944 

85 

5.508 

30 

462.  97 

85 

1311.  75 

31 

2.009 

86 

5.573 

31 

478.  40 

86 

1327.  18 

32 

2.074 

87 

5.638 

32 

493.84 

87 

1342.  62 

33 

2.138 

88 

5.702 

33 

509.27 

88 

1358.  05 

34 

2.203 

89 

5.767 

34 

524.  70 

89 

1373.  48 

35 

2.268 

90 

5.832 

35 

540.  13 

90 

1388.  91 

36 

2.333 

91 

5.897 

36 

555.  56 

91 

1404.34 

37 

2.398 

92 

5.962 

37 

571.00 

92 

1419.  78 

38 

2.462 

93 

6.C26 

38 

586.  43 

93 

1435.  21 

39 

2.527 

94 

6.091 

39 

601.  86 

94 

1450.  64 

40 

2.592 

95 

6.156 

40 

617.29 

95 

1466.  07 

41 

2.657 

96 

6.221 

41 

632.  73 

96 

1481.  51 

42 

2.722 

97 

6.285 

42 

648.16 

97 

1496.  94 

43 

2.786 

98 

6.350 

43 

663.  59 

98 

1512.  37 

44 

2.851 

99 

6.415 

44 

679.  02 

99 

1527.  80 

45 

2  916 

100 

6.480 

45 

694.46 

100 

1543.  24 

46 
47 
48 
49 

2.981 
3.046 
3.110 
3.175 

200 
300 
400 
500 

12.960 
19.440 
25.  920 
32.399 

46 
47 
48 
49 

709.89 
725.  32 
740.75 
756.  19 

200 
300 
400 
500 

3086.  47 
4629.  71 
6172.  94 
7716.  18 

50 
51 
52 
53 
54 

3.240 
3.305 
3.370 
3.434 
3.499 

600 
700 
800 
900 
1000 

38.879 
45.  359 

5&319 
64.799 

50 
51 
52 
53 
54 

771.  62 
787.  05 
802.48 
817.91 
833.35 

600 

700 
800 
900 
1000 

9259.  41 
10802.  65 
12345.  89 
13889.  12 
15432.  36 

24  Circular  of  the  Bureau  of  Standards 

MASS— PENNYWEIGHTS   AND    GRAMS 


TABLE  34 

TABLE  35 

[1  pennyweight=  1.55517404  grams] 

[1  gram=  0.64301485  pennyweight] 

5SK  o— 

SB'  Grams 

55B0""- 

wligWs  Grams 

*—  558 

<*—  £5S 

0.  00   0.  000 

0.  55   0.  855 

0    0.000 

55    85.  535 

0    0.000 

55   35.  366 

.  01    .  016 

.  56    .  871 

1    1.  555 

56    87.  090 

1     .643 

56   36.  009 

.  02    .  031 

.  57    .  886 

2    3.  110 

57    88.  645 

2    1.  286 

57   36.  652 

.03    .047 

.58    .902 

3    4.  666 

58    90.  200 

3    1.  929 

58   37.  295 

.04    .062 

.  59    .  918 

4    6.  221 

59    91.  755 

4    2.  572 

59   37.  938 

.  05    .  078 

.  60    .  933 

5    7.  776 

60    93.  310 

5    3.  215 

60   38.  581 

.06    .093 

.  61    .  949 

6    9.  331 

61    94.  866 

6    3.  858 

61   39.  224 

.07    .109 

.62    .964 

7   10.  886 

62    96.  421 

7    4.  501 

62   39.  867 

.  08    .  124 

.  63    .  980 

8   12.  441 

63    97.  976 

8    5.144 

63   40.  510 

.  09    .  140 

.64    .995 

9   13.  997 

64    99.  531 

9    5.  787 

64   41.  153 

.  10    .  156 

.  65   1.  Oil 

10   15.  552 

65   101.  086 

10    6.  430 

65   41.  796 

.  11    .  171 

.  66   1.  026 

11   17.  107 

66   102.  641 

11    7.  073 

66   42.  439 

.  12    .  187 

.  67   1.  042 

12   18.  662 

67   104.  197 

12    7.  716 

67   43.  082 

.  13    .  202 

.  68   1.  058 

13   20.  217 

68   105.  752 

13    8.359 

68   43.  725 

.  14    .  218 

.69   1.073 

14   21.  772 

69   107.  307 

14    9.  002 

69   44.  368 

.  15    .  233 

.  70     089 

15   23.  328 

70   108.  862 

15    9.  645 

70   45.011 

.  16    .  249 

.  71     104 

16   24.  883 

71    110.  417 

16   10.  288 

71   45.  654 

.17    .264 

.  72     120 

17   26.  438 

72   111.973 

17   10.  931 

72   46.  297 

.  18    .  280 

.  73     135 

18   27.  993 

73   113.  528 

18   11.  574 

73   46.  940 

.  19    .  295 

.  74     151 

19   29.  548 

74   115.  083 

19   12.  217 

74   47.  583 

.  20    .  311 

.75     166 

20   31.  103 

75   116.  638 

20   12.  860 

75   48.  226 

.  21    .  327 

.  76     182 

21   32.  659 

76   118.  193 

21    13.  503 

76   48.  869 

.  22    .  342 

.  77     197 

22   34.  214 

77   119.  748 

22   14.  146 

77   49.  512 

.  23    .  358 

.  78     213 

23   35.  769 

78   121.  304 

23   14.  789 

78   50.  155 

.  24    .  373 

.  79    .  229 

24   37.  324 

79   122.  859 

24   15.  432 

79   50.  798 

.  25    .  389 

.80     244 

25   38.  879 

80   124.  414 

25    16.  075 

80   51.  441 

.26    .404 

.  81     260 

26   40.  435 

81    125.  969 

26   16.  718 

81   52.  084 

.  27    .  420 

.  82     275 

27   41.  990 

82   127.  524 

27   17.  361 

82   52.  727 

.  28    .  435 

.  83     291 

28   43.  545 

83   129.  079 

28   18.  004 

83   53.  370 

.  29    .  451 

.  84     306 

29   45.  100 

84   130.  635 

29   18.  647 

84   54.  013 

.30    .467 

.  85    .  322 

30   46.  655 

85   132.  190 

30   19.  290 

85   54.  656 

.  31    .  482 

.  86     337 

31   48.  210 

86   133.  745 

31    19.  933 

86   55.  299 

.  32    .  498 

.  87    .  353 

32   49.  766 

87   135.  300 

32   20.  576 

87   55.  942 

.33    .513 

.  88    .  369 

33   51.  321 

88   136.  855 

33   21.  219 

88   56.  585 

.  34    .  529 

.89    .384 

34   52.  876 

89   138.  410 

34   21.  863 

89   57.  228 

.  35    .  544 

.90    .400 

35   54.  431 

90   139.  966 

35   22.  506 

90   57.  871 

.36    .560 

.  91    .  415 

36   55.  986 

91    141.  521 

36   23.  149 

91   58.  514 

.  37    .  575 

.  92    .  431 

37   57.  541 

92    143.  076 

37   23.  792 

92   59.  157 

.  38    .  591 

.93    .446 

38   59.  097 

93   144.  631 

38   24.  435 

93   59.  800 

.  39    .  607 

.  94    .  462 

39   60.  652 

94    146.  186 

39   25.  078 

94   60.  443 

.  40    .  622 

.  95    .  477 

40   62.  207 

95   147.  742 

40   25.  721 

95   61.  086 

.  41    .  638 

.  96    .  493 

41   63.  762 

96   149.  297 

41   26.  364 

96   61.  729 

.  42    .  653 

.97    .509 

42   65.  317 

97   150.  852 

42   27.  007 

97   62.  372 

.  43    .  669 

.98    .524 

43   66.  872 

98   152.  407 

43   27.  650 

98   63.  015 

.44    .684 

.  99    .  540 

44   68.  428 

99   153.  962 

44   28.  293 

99   63.  658 

.  45    .  700 

1.00   1.555 

45   69.  983 

100   155.  517 

45   28.  936 

100   64.  301 

.  46    .  715 

46   71.  538 

200   311.  035 

46   29.  579 

200   128.  603 

.  47    .  731 

47   73.  093 

300   466.  552 

47   30.  222 

300   192.  904 

.48    .746 

48   74.  648 

400   622.  070 

48   30.  865 

400   257.  206 

.  49    .  762 

1A   0.194 

49   76.  204 

500   777.  587 

49   31.  508 

500   321.  507 

%    .389 

.50    .778 

H    .583 

50   77.  759 

600   933.  104 

50   32.  151 

600   385.  809 

.  51    .  793 

%    .778 

51   79.  314 

700   1088.  622 

51   32.  794 

700   450.110 

.52    .809 

fi    .972 

52   80.  869 

800   1244.  139 

52   33.  437 

800   514.  412 

.53    .824 

Y4   1.  166 

53   82.  424 

900   1399.  657 

53   34.  080 

900   578.  713 

.54    .840 

H   1.361 

54   83.  979 

1000   1555.  174 

54   34.  723 

1000   643.  015 

Jewelers'  Weights  and  Measures 
MASS— TROY  OUNCES  AND  GRAMS 


TABLE  36 

TABLE  37 

[Itroy  ounce=  31.  1034808  grams] 

[1  gram=0.03215074  troy  ounce] 

ounc'e  Grams  '  ounc'e  Grams 

ounces  <*"»» 

ounces  Grams 

G'ams  ounce's 

Grams  ounc^ 

0.  00   0.  000 
.01    .311 
.  02    .  622 
.  03    .  933 
.  04   1.  244 

0.  55   17.  107 
.  56   17.  418 
.  57   17.  729 
.  58   18.  040 
.  59   18.  351 

0     0.  000 
1    31.  103 
2    62.  207 
3    93.  310 
4   124.  414 

55   1710.  691 
56   174i:  795 
57   1772.  898 
58   1804.  002 
59   1835.  105 

0   0.0000 
1    .  0322 
2    .0643 
3    .0965 
4    .  1286 

55   1.  7683 
56   1.  8004 
57   1.  8326 
58   1.  8647 
59   1.  8969 

.  05   1.  555 
.  06   1.  866 
.  07   2.  177 
.  08   2.  488 
.  09   2.  799 

.  60   18.  662 
.  61   18.  973 
.  62   19.  284 
.  63   19.  595 
.  64   19.  906 

5   155.  517 
6   186.  621 
7   217.  724 
8   248.  828 
9   279.  931 

60   1866.  209 
61   1897.  312 
62    1928.  416 
63   1959.  519 
64   1990.623 

5    .  1608 
6    .  1929 
7    .  2251 
8    .  2572 
9    .2894 

•  60   1.9290 
61   1.  9612 
62   1.  9933 
63   2.  0255 
64   2.  0576 

.  10   3.  110 
.11   3.421 
.  12   3.  732 
.  13   4.  043 
.  14   4.  354 

.  65   20.  217 
.66   20.528 
.  67   20.  839 
.  68   21.  150 
.  69   21.  461 

10   311.  035 
11   342.  138 
12   373.  242 
13   404.  345 
14   435.  449 

65   2021.  726 
66   2052.  830 
67   2083.  933 
68   2115.  037 
69   2146.  140 

10    .  3215 
11    .  3537 
12    .  3858 
13    .  4180 
14    .  4501 

65   2.  0898 
66   2.  1219 
67   2.  1541 
68   2.  1863 
69   2.  2184 

.  15   4.  666 
.  16   4.  977 
.  17   5.  288 
.  18   5.  599 
.  19   5.  910 

.  70   21.  772 
.  71   22.  083 
.  72   22.  395 
.  73   22.  706 
.  74   23.  017 

15   466.  552 
16   497.  656 
17   528.  759 
18   559.  863 
19   590.  966 

70   2177.  244 
71   2208.  347 
72   2239.  451 
73   2270.  554 
74   2301.  658 

15    .  4823 
16    .  5144 
17    .  5466 
18    .  5787 
19    .  6109 

70   2.  2506 
71   2.  2827 
72   2.  3149 
73   2.  3470 
74   2.  3792 

.  20   6.  221 
.  21   6.  532 
.  22   6.  843 
.  23   7.  154 
.  24   7.  465 

.  75   23.  328 
.  76   23.  639 
.  77   23.  950 
.  78   24.  261 
.  79   24.  572 

20   622.  070 
21   653.  173 
22   684.  277 
23   715.  380 
24   746.  484 

75   2332.  761 
76   2363.  865 
77   2394.  968 
78   2426.  071 
79   2457.  175 

20    .  6430 
21    .  6752 
22    .  7073 
23    .  7395 
24    .  7716 

75   2.4113 
76   2.  4435 
77   2.  4756 
78   2.  5078 
79   2.  5399 

.  25   7.  776 
.  26   8.  087 
.  27   8.  398 
.  28   8.  709 
.  29   9.  020 

.  80   24.  883 
.  81   25.  194 
.  82   25.  505 
.  83   25.  816 
.  84   26.  127 

25   777.  587 
26   808.  690 
27   839.  794 
28   870.  897 
29   902.  001 

80   2488.  278 
81   2519.  382 
82   2550.  485 
83   2581.  589 
84   2612.  692 

25    .  8038 
26    .  8359 
27    .  8681 
28    .  9002 
29    .  9324 

80   2.  5721 
81   2.  6042 
82   2.  6364 
83   2.  6685 
84   2.  7007 

.  30   9.  331 
.  31   9.  642 
.  32   9.  953 
.  33   10.  264 
.  34   10.  575 

.  85   26.  438 
.  86   26.  749 
.  87   27.  060 
.  88   27.  371 
.  89   27.  682 

30   933.  104 
31   964.  208 
32   995.  311 
33   1026.  415 
34   1057.  518 

85   2643.  796 
86   2674.  899 
87   2706.  003 
88   2737.  106 
89   2768.  210 

30    .9645 
31    .  9967 
32    .  0288 
33    .  0610 
34    .  0931 

85   2.  7328 
86   2.  7650 
87   2.  7971 
88   2.  8293 
89   2.  8614 

.  35   10.  886 
.  36   11.  197 
.  37   11.  508 
.  38   11.  819 
.  39   12.  130 

.  90   27.  993 
.  91   28.  304 
.92   28.615 
.  93   28.  926 
.94   29.237 

35   1088.  622 
36   1119.  725 
37   1150.  829 
38   1181.  932 
39   1213.  036 

90   2799.  313 
91   2830.  417 
92   2861.  520 
93   2892.  624 
94   2923.  727 

35    .  1253 
36    .  1574 
37    .  1896 
38    .  2217 
39    .  2539 

90   2.  8936 
91   2.  9257 
92   2.  9579 
93   2.  9900 
94   3.  0222 

.  40   12.  441 
.  41   12.  752 
.  42   13.  063 
.  43   13.  374 
.44   13.686 

.  95   29.  548 
.  96   29.  859 
.  97   30.  170 
.  98   30.  481 
.99   30.792 

40   1244.  139 
41   1275.  243 
42   1306.  346 
43   1337.  450 
44   1368.  553 

95   2954.  831 
96   2985.  934 
97   3017.  038 
98   3048.  141 
99   3079.  245 

40    .  2860 
41    .  3182 
42    .  3503 
43    .  3825 
44    .  4146 

95   3.  0543 
96   3.  0865 
97   3.  1186 
98   3.  1508 
99   3.  1829 

.  45   13.  997 
.  46   14.  308 
.  47   14.  619 
.48   14.930 
.  49   15.  241 

1.  00   31.  103 

45   1399.  657 
46   1430.  760 
47   1461.  864 
48   1492.  967 
49   1524.  071 

100   3110.  348 
200   6220  696 
300   9331.  044 
400   12441.  392 
500   15551.  740 

45   1.  4468 
46   1.  4789 
47   1.  5111 
48   1.  5432 
49   1.  5754 

100   3.  2151 
200   6.  4301 
300   9.  6452 
400   12.  8603 
500   16.  0754 

.  50   15.  552 
.  51   15.  863 
.  52   16.  174 
.  53   16.  485 
.54   16.  796 

50   1555.  174 
51   1586.  278 
52   1617.  381 
53   1648.  484 
54   1679.  588 

600   18662.  088 
700   21772.  437 
800   24882.  785 
900   27993.  133 
1000   31103.  481 

50   1.  6075 
51   1.  6397 
52   1.  6718 
53   1.  7040 
54   1.  7361 

600   19.  2904 
700   22.  5055 
800   25.  7206 
900   28.  9357 
1000   32.  1507 

26  Circular  of  the  Bureau  of  Standards 

MASS— POUNDS    AND    KILOGRAMS 


TABLE  38 

TABLE  39 

[1  avoirdupois  pound=  0.45359  24277  kilogram] 

[1  kilogram=2.20462234  avoirdupois  pounds] 

Avoir- 

Avoir- 

Avoir- 

Avoir- 

dupois 
pounds0 

Kilograms  «             dupois  Kilograms 
pounds 

Kilograms  " 

dupois 
pounds" 

Kilograms 

dupois 
pounds 

0 

0.0 

55 

24.9 

0 

0.0 

55 

121.3 

1 

.5 

56 

25.4 

1 

2.2 

56 

123.5 

2 

.9 

57 

25.9 

2 

4.4 

57 

125.7 

3 

1.4 

58 

26.3 

6.6 

58 

127.9 

4 

.1.8 

59 

26.8 

8.8 

59 

130.1 

5 

2.3 

60 

27.2 

11.0 

60 

132.3 

6 

2.7 

61 

27.7 

13.2 

61 

134.5 

7 

3.2 

62 

28.1 

15.4 

62 

136.7 

8 

3.6 

63 

28.6 

17.6 

63 

138.9 

9 

4.1 

64 

29.0 

19.8 

64 

141.1 

10 

4.5 

65 

29.5 

10 

22.0 

65 

143.3 

11 

5.0 

66 

29.9 

11 

24.3 

66 

145.5 

12 

5.4 

67 

30.4 

12 

26.5 

67 

147.7 

13 

5.9 

68 

30.8 

13 

28.7 

68 

149.9 

14 

6.4 

69 

31.3 

14 

30.9 

69 

152.1 

15 

6.8 

70 

31.8 

15 

33.1 

70 

154.3 

16 

7.3 

71 

32.2 

16 

35.3 

71 

156.5 

17 

7.7 

72 

32.7 

ir 

37.5 

72 

158.7 

18 

8.2 

73 

33.1 

18 

39.7 

73 

160.9 

19 

8.6 

74 

33.6 

19 

41.9 

74 

163.1 

20 

9.1 

75 

34.0 

20 

44.1 

75 

165.3 

21 

9.5 

76 

34.5 

21 

46.3 

76 

167.6 

22 

10.0 

77 

34.9 

22 

48.5 

77 

169.8 

23 

10.4 

78 

35.4 

23 

50.7 

78 

172.0 

24 

10.9 

79 

35.8 

24 

52.9 

79 

174.2 

25 

11.3 

80 

36.3 

25 

55.1 

80 

176.4 

26 

11.8 

81 

36.7 

26 

57.3 

81 

178.6 

27 

12.2 

82 

37.2 

27 

59.5 

82 

180.8 

28 

12.7 

83 

37.6 

28 

61.7 

83 

183.0 

29 

13.2 

84 

38.1 

29 

63.9 

84 

185.2 

30 

13.6 

85 

38.6 

30 

66.1 

85 

187.4 

31 

14.1 

86 

39.0 

31 

68.3 

86 

189.6 

32 

14.5 

87 

39.5 

32 

70.5 

87 

191.8 

33 

15.0 

88 

39.9 

33 

72.8 

88 

194.0 

34 

15.4 

40.4 

34 

75.0 

89 

196.2 

35 

15.9 

90 

40.8 

35 

77.2 

90 

198.4 

36 

16.3 

91 

41.3 

36 

79.4 

91 

200.6 

37 

16.8 

92 

41.7 

37 

81.6 

92 

202.8 

38 

17.2 

93 

42.2 

38 

83.8 

93 

205.0 

39 

17.7 

94 

42.6 

39 

86.0 

94 

207.2 

40 

18.1 

95 

43.1 

40 

88.2 

95 

209.4 

41 

18.6 

96 

43.5 

41 

90.4 

96 

211.6 

42 

19.1 

97 

44.0 

42 

92.6 

97 

213.8 

43 

19.5 

98 

44.5 

43 

94.8 

98 

216.1 

44 

20.0 

99 

44.9 

44 

97.0 

99 

218.3 

45 

20.4 

100 

45.4 

45 

99.2 

100 

220.5 

46 

20.9 

200 

90.7 

46 

101.4 

200 

440.9 

47 

21.3 

300 

136.1 

47 

103.6 

300 

661.4 

48 

21.8 

400 

181.4 

48 

105.8 

400 

881.8 

49 

22.2 

500 

226.8 

49 

108.0 

500 

1102.3 

50 

22.7 

600 

272.2 

50 

110.2 

600 

1322.  8 

51 

23.1 

700 

317.5 

51 

112.4 

700 

1543.  2 

52 

23.6 

800 

362.9 

52 

114.6 

800 

1763.  7 

53 

24.0 

900 

408.2 

53 

116.8 

900 

1984.  2 

54 

24.  5                         1000 

453.6 

54 

119.0 

1000 

2204.  6 

1  For  the  conversion  of  avoirdupois  ounces  to  grams  see  Table  29. 


Jewelers1  Weights  and  Measures  27 

III.  THE  METRIC  CARAT 
1.  DEFINITION 

The  carat  which  had  been  in  use  prior  to  July  i,  1913,  in  the 
United  States,  while  varying,  has  been  nearer  the  value  205.3  mg 
than  any  other.  This  value  has  therefore  been  taken  in  making 
up  the  tables  of  equivalents  given  in  this  circular.  The  old  carat 
has  usually  been  subdivided  on  the  binary  system,  the  smallest 
subdivision  used  being  usually  one  sixty-fourth  of  the  carat.  The 
equivalents  in  fractions  of  a  carat  in  these  tables  are,  therefore, 
given  in  sixty-fourths.  One  of  the  improvements  introduced  with 
the  new  carat  of  exactly  200  mg  is  the  subdivision  of  it  on  the 
decimal  system.  The  fractions  of  the  new  carat  in  these  tables 
are  accordingly  given  to  hundredths  of  a  carat. 

2.  CONVERSION  TABLES 

Tables  40  and  41  are  for  the  conversion  of  quantities  in  the  old 
unit  to  the  equivalent  weight  in  terms  of  the  new  metric  carat. 
Table  40  is  used  for  the  conversion  of  fractions  of  a  carat,  while 
Table  41  gives  the  equivalent  of  each  unit  or  whole  carat  from  i  to 
100  of  the  old  system  in  terms  of  new  metric  carats  and  hun- 
dredths of  a  carat.  If  it  is  desired  to  convert  whole  carats  and 
fractions  of  a  carat  of  the  old  unit  to  the  new,  the  two  tables  can 
be  used  in  combination;  that  is,  by  adding  the  quantities  obtained 
from  each,  thus:  Suppose  it  is  desired  to  obtain  the  equivalent 
of  28|i  old  carats  in  terms  of  the  metric  carats: 

From  Table  40.  .        M  old  carats  =  o.  72  metric  carats 
From  Table  41 ..   28      old  carats  =  28.  74  metric  carats 


Adding.  . .    28|f  old  carats  =  29. 46  metric  carats. 

Or,  if  it  is  desired  to  convert  a  larger  quantity  involving  several 
hundred  or  thousand  carats,  one  uses  the  equivalents  in  the  last 
column  of  Table  41  for  each  hundred  and  thousand  of  the  old  carats 
up  to  ten  hundred  and  ten  thousand — thus,  to  convert  3225!  old 
carats  to  metric  carats: 

From  Table  40.  .  f  old  carats  =       o.  77  metric  carats 

From  Table  41 ..       25    old  carats  =     25.  66  metric  carats 

200    old  carats  =-   205.  30  metric  carats 

3000    old  carats  =  3079.  50  metric  carats 

Adding.  .  .   3225!  old  carats  =  331 1 .  23  metric  carats. 


28 


Circular  of  the  Bureau  of  Standards 


TABLE  40.— Equivalents  of  Fractions  of  the  Old  Carat  Weight  in  New  Decimal 
Metric  Carats 


[Computed  on  the  basis  of  1  old  carat  =  205.3  mg; 


r  metric  carat=200  mg] 


Old  carat 

New 
metric 
carats 

Old  carat 

New 
metric 
carats 

1/2's 

1/4's 

8ths 

leths 

32ds 

64ths 

1 

1  carat 

1/2's 

1/4's 

8ths 

leths 

32ds 

64ths 

=  0.02 

33 

=  0.53 

1 

2 

=  .03 

17 

34 

=  .55 

3 

=  .05 

35 

=  .56 

i 

2 

4 

=  .06 

9 

18 

36 

=  .58 

5 

=  .08 

37 

=  .59 

3 

6 

=  .10 

19 

38 

=  .61 

7 

=  .11 

39 

=  .63 

1 

2 

4 

8 

=  .13 

5 

10 

20 

40 

=  .64 

9 

=  .14 

41 

=  .66 

5 

10 

=  .16 

21 

42 

=  .67 

11 

=  .18 

43 

=  .69 

3 

6 

12 

=  .19 

11 

22 

44 

=  .71 

13 

=  .21 

45 

=  .72 

7 

14 

=  .22 

23 

46 

=  .74 

15 

=  .24 

47 

=  .75 

1 

2 

4 

8 

16 

=  .26 

3 

6 

12 

24 

48 

=  .77 

17 

=  .27 

49 

=  .79 

9 

18 

=  .29 

25 

50 

=  .80 

19 

=  .30 

51 

=  .82 

5 

10 

20 

=  .32 

13 

26 

52 

=  .83 

21 

=  .34 

53 

=  .85 

11 

22 

=  .35 

27 

54 

=  .87 

23 

=  .37 

55 

=  .88 

3 

6 

12 

24 

=  .38 

7 

14 

28 

56 

=  .90 

25 

=  .40 

57 

=  .91 

13 

26 

=  .42 

29 

58 

=  .93 

27 

=  .43 

59 

=  .95 

7 

14 

28 

=  .45 

15 

30 

60 

=  .96 

29 

=  .47 

61 

=  .98 

15 

30 

=   .48 

31 

62 

=  .99 

31 

=  .50 

63 

=  1.01 

1 

2 

4 

8 

16 

32 

=  .51 

1 

2 

4 

8 

16 

32    1     64 

-1.03 

Jewelers'  Weights  and  Measures  29 

TABLE  41.— Equivalents  of  the  Old  Carats  in  New  Decimal  Metric  Carats 

[Computed  on  the  basis  of  1  old  carat=  205.3  mg;  1  new  metric  carat=200  mg] 


Old 

carats 

New 
metric 
carats 

Old 

carats 

New 
metric 
carats 

Old 
carats 

New 
metric 
carats 

Old 

carats 

New 
metric 
carats 

Old 

carats 

New 
metric 
carats 

1 

1.03 

26 

26.69 

51 

52.35 

76 

78.01 

200 

205.30 

2 

2.05 

27 

27.72 

52 

53.38 

77 

79.04 

300 

307.95 

3.08 

28 

28.74 

53 

54.40 

78 

80.07 

400 

410.60 

4.11 

29 

29.77 

54 

55.43 

-      79 

81.09 

500 

513.  25 

5.13 

30 

30.80 

55 

56.46 

80 

82.12 

600 

615.90 

6.16 

31 

31.82 

56 

57.48 

81 

83.  15 

700 

718.  55 

7.19 

32 

32.85 

57 

58.51 

82 

84.17 

800 

821.  20 

8.21 

33 

33.87 

58 

59.54 

83 

85.20 

900 

923.  85 

9.24 

34 

34.90 

59 

60.56 

84 

86.23 

1000 

1026.  50 

10 

10.26 

35 

35.93 

60 

61.59 

85 

87.25 

2000 

2053.  00 

11 

11.29 

36 

36.95 

61 

62.62 

86 

88.28 

3000 

3079.  50 

12 

12.32 

37 

37.98 

62 

63.64 

87 

89.31 

4000 

4106.00 

13 

13.34 

38 

39.01 

63 

64.67 

90.33 

5000 

5132.  50 

14 

14.37 

39 

40.03 

64 

65.70 

89 

91.36 

6000 

6159.  00 

15 

15.40 

40 

41.06 

65 

66.72 

90 

92.38 

7000 

7185.  50 

16 

16.42 

41 

42.09 

66 

67.75 

91 

93.41 

8000 

8212.  00 

17 

17.45 

42 

43.11 

67 

68.78 

92 

94.44 

9000 

9238.  50 

18 

18.48 

43 

44.14 

68 

69.80 

93 

95.46 

10  000 

10265.  00 

19 

19.50 

44 

45.  17  . 

69 

70.83 

94 

96.49 

20 

20.53 

45 

46.19 

70 

71.86 

95 

97.52 

21 

21.56 

46 

47.22 

71 

72.88 

96 

98.54 

22 

22.58 

47 

48.25 

72 

73.91 

97 

99.57 

23 

23.61 

48 

49.27 

73 

74.93 

98 

100.60 

24 

24.64 

49 

50.30 

74 

75.96 

99 

101.  62 

25 

25.66 

50 

51.32 

75 

76.99 

100 

102.  65 

IV.  GAGES7   (WIRE  AND  DRILL) 
1.  EXISTING  PRACTICE  IN  GAGING  MATERIALS 

The  sizes  of  materials  were  for  many  years  indicated  in  commer- 
cial practice  almost  entirely  by  gage  numbers.  This  practice 
was  accompanied  by  considerable  confusion  because  numerous 
gages  were  in  use.  In  general,  gage  sizes  are  used  much  less 
now  than  formerly.8 

In  so  far  as  wire  gages  are  now  in  use  in  the  United  States, 
the  practice  has  been  practically  limited  to  the  use  of  two  gages. 
For  iron  plates,  there  is  only  one  gage — viz,  the  "  U.  S.  standard." 
For  drills  there  are  two,  with  an  additional  one  for  drill  rod  and 
steel  wire.  Finally,  there  are  some  special  gages,  including 
several  music  wire  gages. 

The  trend  of  practice  in  the  gaging  of  materials  is  increasingly 
toward  the  direct  specification  of  the  dimensions  in  decimal  frac- 
tions of  an  inch  or  millimeter  without  the  use  of  gage  numbers. 
Numerous  engineering  societies  have  gone  on  record  as  in  favor 
of  the  direct  use  of  diameters.  This  is  similar  to  the  practice 
in  Germany,  France,  and  Italy,  where  sizes  are  specified  directly 
by  the  diameter  in  millimeters. 

7  This  information  about  gages  was  gathered  from  the  statements  on  the  subject  in  the  catalogues  of 
manufacturers  and  in  scientific  literature,  including  B.  S.  Circular  No.  31. 

8  In  an  article  written  in  1887  (S.  S.  Wheeler,  Elec.  World,  10,  p.  254;  1887),  over  30  gages  were  described, 
19  of  which  were  wire  gages. 


30  Circular  of  the  Bureau  of  Standards 

2.  WIRE  GAGES  9 

Among  the  wire  gages  that  have  survived,  two  are  used  exten- 
sively in  this  country,  viz,  the  "American  wire  gage"  (Brown 
&  Sharpe)  and  the  "Steel  wire  gage"  (variously  called  the 
"Washburn  &  Moen,"  "  Roebling,"  and  "American  Steel  &  Wire 
Co.'s").  Three  other  gages  are  still  used  to  some  extent,  viz,  the 
"Stubs'  steel  wire  gage,"  the  "Birmingham  wire  gage"  (Stubs), 
and  the  "Old  English  wire  gage"  (London).  In  England  one 
wire  gage  has  been  made  legal  and  is  in  use  generally,  viz,  the 
"Standard  wire  gage."  The  diameters  corresponding  to  the  gage 
number  of  five  of  the  general  wire  gages  mentioned  are  given  in 
both  inches  and  in  millimeters  in  Table  43. 

(a)  American  wire  gage 

The  American  wire  gage  is  frequently  called  the  "  Brown  & 
Sharpe  gage."  Its  sizes  are  not  utterly  arbitrary  and  the  differ- 
ences between  successive  diameters  are  more  regular  than  those 
of  other  gages.  It  is  the  only  wire  gage  now  in  use  whose  suc- 
cessive sizes  are  determined  by  a  mathematical  law.  The  law 
of  geometrical  progression  on  which  the  gage  is  based  is  that  the 
ratio  of  any  diameter  to  the  next  smaller  is  a  constant  number 
(i . 1 229322) .  It  is  derived  from  the  fundamental  definition  of  the 
gage,  which  is  that  size  No.  4-0  shall  be  0.4600  inch  in  diameter, 
size  No.  36  shall  be  0.0050  inch  in  diameter,  and  38  intermediary 
sizes  or  diameters  shall  be  formed  by  geometrical  progression. 

(b)  Steel  wire  gage 

The  "Steel  wire  gage"10  with  a  number  of  its  sizes  expressed 
only  to  the  nearest  thousandth  of  an  inch,  has  been  known  as 
the  Roebling  gage.  It  was  originally  established  about  the 
year  1830,  and  was  named  after  the  Washburn  &  Moen  Manufac- 
turing Co.  This  company  was  later  merged  into  the  American 
Steel  &  Wire  Co.,  which  continued  the  use  of  the  Washburn  & 
Moen  gage  for  steel  wire,  giving  it  the  name  "American  Steel  & 
Wire  Co.'s  gage." 

(c)  Stubs'  steel  wire  gage 

The  Stubs'  steel  wire  gage  has  a  somewhat  limited  use  for  tool 
steel  wire  and  drill  rods.  This  gage  should  not  be  confused  with 
the  Birmingham  wire  gage,  which  is  sometimes  known  as  Stubs' 

8  For  a  more  complete  discussion  of  wire  gages,  see  B.  S.  Circular  No.  31,  Copper  Wire  Tables. 

10  The  name  "Steel  wire  gage"  was  suggested  by  the  Bureau  of  Standards  in  its  correspondence  with 
various  companies,  and  it  met  with  practically  unanimous  approval.  It  was  necessary  to  decide  upon  a 
name  for  this  gage,  and  the  three  names  which  have  been  used  for  it  in  the  past  were  all  open  to  the  objec- 
tion that  they  were  the  names  of  particular  companies.  These  companies  have  accepted  the  new  name. 
The  abbreviation  of  the  name  of  the  gage  should  be  "Stl.  W.  G.,"  to  distinguish  it  from  "S.  W.  G.,"  the 
abbreviation  for  the  (British)  Standard  wire  gage.  When  it  is  necessary  to  distinguish  the  name  of  this 
gage  from  others  which  may  be  used  for  steel  wire— e.  g.,  the  (British)  Standard  wire  gage — it  may  be  called 
the  United  States  steel  wire  gage. 


Jewelers'  Weights  and  Measures  31 

iron  wire  gage.  The  diameters  of  its  sizes  are  very  nearly  iden- 
tical with  the  diameters  of  the  corresponding  sizes  of  drill  gages, 
as  is  shown  in  Tables  45,  46,  and  47. 

(d)  BIRMINGHAM  WIRE  GAGE 

Of  the  various  wire  gages  which  have  remained  in  use  but  are 
now  nearly  obsolete,  the  one  most  frequently  mentioned  is  the  Bir- 
mingham. Its  steps  are  quite  irregular.  Some  of  the  later  gages 
were  based  on  the  Birmingham,  and  by  the  repeated  copying  of 
old  specifications  its  use  has  persisted  to  some  extent,  both  in 
England  and  the  United  States.  In  the  past  this  gage  held 
certain  departmental  sanction  in  the  United  States  Government, 
but  this  sanction  was  removed  in  1914. 

(e)  STANDARD  WIRE  GAGE 

The  "Standard  wire  gage,"  otherwise  known  as  the  new  British 
standard,  the  English  legal  standard,  or  the  Imperial  wire  gage, 
is  the  legal  standard  of  Great  Britain  for  all  wires,  as  fixed  by  order 
in  Council,  August  23,  1883.  It  was  constructed  by  improving  the 
Birmingham  wire  gage. 

(f)  OLD  ENGLISH  OR  LONDON  GAGE 

The  Old  English  or  London  gage,  the  sizes  of  which  differ  very 
little  from  those  of  the  Birmingham  gage,  has  had  considerable 
use  in  the  past  for  brass  and  copper  wires,  and  is  now  used  to  some 
extent  in  the  drawing  of  brass  wire  for  weaving.  It  is  nearly 

obsolete. 

3.  TWIST  DRILL  AND  STEEL  WIRE  GAGES 

The  confusion  in  the  use  of  gages  for  twist  drills,  drill  rod,  and 
steel  wire  is  a  constant  source  of  trouble.  The  differences  between 
the  diameters  of  the  corresponding  sizes  of  the  various  gages  are 
very  small,  generally  being  less  than  0.002  inch.  In  this  field 
also,  the  manufacturers  (of  drills)  are  encouraging  the  direct  use 
of  diameters  in  place  of  specifying  sizes  by  gage  numbers.  At 
the  present  time  there  are  three  gages  in  extensive  use  in  this 
field.  These  are  (i)  the  Stubs'  steel  wire  gage,  (2)  the  drill  gage 
used  by  the  Standard  Tool  Co.,  and  (3)  the  drill  gage  used  by 
various  other  leading  manufacturers  of  twist  drills.  This  latter 
gage  is  referred  to  in  the  tables  which  follow  as  "various  manu- 
facturers "  but  in  other  publications  it  is  sometimes  referred  to  as 
' '  manufacturers '  standard. ' ' 

All  of  these  gages  have  26  lettered  sizes  and  80  numbered  sizes. 
The  lettered  sizes  of  all  three  gages  are  identical.  (See  Table  44.) 
For  the  numbered  sizes,  the  Stubs'  steel  wire  gage  does  not  agree 
with  either  of  the  drill  gages.  For  Nos.  i  to  60  (Table  45)  the 
gage  of  the  Standard  Tool  Co.  agrees  with  the  corresponding  sizes 


Circular  of  the  Bureau  of  Standards 


of  the  gage  used  by  various  other  manufacturers;  for  sizes  Nos.  61 
to  80  (Tables  46  and  47)  there  are  numerous,  but  small,  differences. 
The  Standard  Tool  Co.  gage  sizes  were  the  original,  which,  for  sizes 
6 1  to  80,  were  changed  by  certain  manufacturers.  The  old  size 
numbers  and  diameters  were  retained  by  the  Standard  Tool  Co., 
which,  in  turn,  began  to  manufacture  drills  of  the  new  diameters 
as  determined  by  the  modified  gage  numbers  of  the  other  manu- 
facturers, but  assigned  them  gage  sizes  by  inserting  so-called  half- 
sizes  into  their  own  gagt.  The  relationships  between  the  diameters 
and  the  various  gage  sizes  are  shown  in  Table  47. 

4.  TABLES  OF  GAGE  SIZES  (INCHES  AND  MILLIMETERS) 

TABLE  42. — DouziSme  Caliper  <* 

[Equivalent  of  each  graduation  on  douzieme  spring  caliper.a     l  douzieme=  1/12  Hgne;  1  ligne=  2.2559  mm] 


Douziemes 

Inch. 

mm 

Douziemes 

Inch 

mm 

0  0074 

0  188 

37 

0  2738 

6  956 

2     

.0148 

.376 

38  

.  2812 

7  144 

3 

0222 

.564 

39  .. 

2886 

7  332 

4  

.0296 

.752 

40  

.2960 

7.520 

5  

6 

.0370 
0444 

.940 
1  128 

41  

42 

.3035 
3109 

7.708 
7  896 

7         

.0518 

1.316 

43  

.3183 

8  084 

8 

0592 

1  504 

44 

3257 

8  272 

9 

0666 

1  692 

45 

3331 

8  460 

10 

0740 

1  880 

46  

3405 

8  648 

11 

0814 

2  068 

47 

3479 

8  836 

1  ligne  -  12    

.0888 

2.256 

4  lignes=48  

.3553 

9.024 

13  

.0962 

2.444 

49  

.3627 

9.212 

1036 

2  632 

50 

3701 

9  400 

15 

1110 

2.820 

51  

.3775 

9  sag 

16 

1184 

3  008 

52 

3849 

9  776 

17           

1258 

3.196 

53  

.3923 

9  964 

18 

1332 

3  384 

54  

3997 

10  152 

19    

.1406 

3.572 

55  

.4071 

10  340 

20  

21 

.1480 
1554 

3.760 
3  948 

56  

57 

.4145 
4219 

10.  528 
10  716 

22           

1628 

4.136 

58  

.4293 

10  904 

23 

1702 

4  324 

59 

4367 

11  092 

2  lignes—  24 

1776 

4  512 

5  lignes=  60 

4441 

11  280 

25 

1850 

4  700 

61   .      

.4515 

11  467 

26 

1924 

4  888 

62 

4589 

11  655 

27  

.1998 

5.076 

63  

.4663 

11.843 

28 

2072 

5  264 

64 

4737 

12  031 

29  

.2146 

5.452 

65  

.4811 

12.  219 

30  

31 

.2220 
2294 

5.640 
5  828 

66  

67 

.4885 
4959 

12.407 
12  595 

32  

.2368 
2442 

6.016 
6  204 

68  
69  . 

.5033 
5107 

12.783 
12  971 

34      

.2516 

6  392 

70  

.5181 

13  159 

35 

2590 

6  580 

71  .. 

5255 

13  347 

3  lignes—  36 

2664 

6  768 

6  lignes—  72 

5329 

13  535 

<*  This  caliper  must  not  be  confused  with  the  tenth-millimeter  spring  caliper,  which  is  similar  in  appear- 
ance to  the  douzieme  caliper.  For  the  graduation  equivalents  of  the  gage,  or  caliper,  referred  to  by  the 
various  names  of  screw,  point,  or  dial  gage,  using  the  values  of  "points"  as  used  by  silversmiths,  or 
quarter-thousandths  of  an  inch,  see  the  first  column  of  Table  6. 


Jewelers'  Weights  and  Measures 
TABLE  43.— Tabular  Comparison  of  Wire  Gages 


33 


Gage  No. 

American 
wire  gage 
(Brown  &  Sharpe) 

Steel  wire  gage  a 

Birmingham 
wire  gage 
(Stubs') 

Stubs'  steel  wire 
gage 

(British) 
Standard  wire 
gage 

Inch 

mm'' 

Inch 

mm 

Inch 

mm 

Inch 

mm 

Inch 

mm 

7-0 

0.4900 
.4615 
.4305 

.3938 
.3625 
.3310 
.3065 

.2830 
.2625 
.2437 
.2253 

.2070 
.1920 
.1770 
.1620 
.1483 

.1350 
.1205 
.1055 
.0915 
.0800 

.0720 
.0625 
.0540 
.0475 
.0410 

.0348 
.0317 
.0286 
.0258 
.0230 

.0204 
.0181 
.0173 
.0162 
.0150 

.0140 
.0132 
.0128 
.0118 
.0104 

.0095 
.0090 
.0085 
.0080 
.0075 

.0070 
.0066 
.0062 
.0060 
.0058 

.0055 
.0052 
.0050 
.0048 
.0046 
.0044 

12.45 
11.72 
10.93 

10.00 
9.21 
8.41 
7.79 

7.19 
6.67 
6.19 
5.72 

5.26 
4.88 
4.50 
4.11 
3.77 

3.43 
3.06 
2.68 
2.32 
2.03 

.829 
.588 
.372 
.207 
.041 

.884 
.805 
.726 
.655 
.584 

.518 
.460 
.439 
.411 
.381 

.356 
.335 
.325 
.300 
.264 

.241 
.229 
.216 
.203 
.191 

.178 
.168 
.157 
.152 
.147 

.140 
.132 
.127 
.122 
.117 
.112 

0.500 
.464 
.432 

.400 
.372 
.348 
.324 

.300 
.276 
.252 
.232 

.212 
.192 
.176 
.160 
.144 

.128 
.116 
.104 
.092 
.080 

.072 
.064 
.056 
.048 
.040 

.036 
.032 
.028 
.024 
.022 

.020 
.018 
.0164 
.0148 
.0136 

.0124 
.0116 
.0108 
.0100 
.0092 

.0084 
.0076 
.0068 
.0060 
.0052 

.0048 
.0044 
.0040 
.0036 
.0032 

.0028 
.0024 
.0020 
.0016 
.0012 
.0010 

12.70 

11.79 
10.97 

10.16 
9.45 
8.84 
8.23 

7.62 
7.01 
6.40 
5.89 

5.38 
4.88 
4.47 
4.06 
3.66 

3.25 
2.95 
2.64 
2.34 
2.03 

1.83 

1.63 
1.42 
1.22 
1.02 

.91 
.81 
.71 
.61 
.56 

.51 
.46 
.417 
.376 
.345 

.315 
.295 
.274 
.254 
.234 

.213 
.193 
.173 
.152 
.132 

.122 
.112 
.102 
.091 
.081 

.071 
.061 
.051 
.041 
.030 
.025 

6-0 

5-0 

4-0  
3-0 

0.4600 
.4096 
.3648 
.3249 

.2893 
.2576 
.2294 
.2043 

.1819 

.1620 
.1443 
.1285 
.1144 

.1019 
.0907 
.0808 
.0720 
.0641 

.0571 
.0508 
.0453 
.0403 
.0359 

.0320 
.0285 
0253 
.0226 
.0201 

.0179 
.0159 
.0142 
.0126 
.0113 

.0100 
.0089 
.0080 
.0071 
.0063 

.0056 
.0050 
.0045 
.0040 
.0035 

.0031 
.0028 
.0025 
.0022 
.0020 

.0018 
.0016 
.0014 
.0012 
.0011 
.0010 

11.68 
10.40 
9.27 
8.25 

7.35 
6.54 
5.83 
5.19 

4.621 
4.115 
3.665 
3.264 
2.906 

2.588 
2.305 
2.053 
1.828 
1.628 

1.450 
1.291 
1.150 
1.024 
.912 

.812 
.723 
.644 
.573 
.511 

.455 
.405 
.361 
.321 
.286 

.255 
.227 
.202 
.180 
.160 

.143 
.127 
.113 
.101 
.090 

.080 
.071 
.063 
.056 
.050 

.045 
.040 
.035 
.032 
.028 
.025 

0.454 
.425 
.380 
.340 

.300 
.284 
.259 
.238 

.220 
.203 
.180 
.165 
.148 

.134 
.120 
.109 
.095 
.083 

.072 
.065 
.058 
.049 
.042 

.035 
.032 
.028 
.025 
.022 

.020 
.018 
.016 
.014 
.013 

.012 
.010 
.009 
.008 
.007 

.005 
.004 

11.53 
10.80 
9.65 

8.64 

7.62 
7.21 
6.58 
6.05 

5.59 
5.16 
4.57 
4.19 
3.76 

3.40 
3.05 
2.77 
2.41 
2.11 

1.83 
1.65 
1.47 
1.24 
1.07 

.889 
.813 
.711 
.635 
.559 

.508 
.457 
.406 
.356 
.330 

.305 
.254 
.229 
.203 
.178 

.127 
.102 

2-0  
0  

2  

0.227 
.219 
.212 
.207 

.204 
.201 
.199 
.197 
.194 

.191 
.188 
.185 
.182 
.180 

.178 
.175 
.172 
.168 
.164 

.161 
.157 
.155 
.153 
.151 

.148 
.146 
.143 
.139 
.134 

.127 
.120 
.115 
.112 
.110 

.108 
.106 
.103 
.101 
.099 

.097 
.095 
.092 
.088 
.085 

.081 
.079 
.077 
.075 
.072 
.069 

5.77 
5.56 
5.38 
5.26 

5.18 
5.11 
5.05 
5.00 
4.93 

4.85 
4.78 
4.70 
4.62 
4.57 

4.52 
4.45 
4.37 
4.27 
4.17 

4.09 
3.99 
3.94 
3.89 
3.84 

3.76 
3.71 
3.63 
3.53 
3.40 

3.23 
3.05 
2.92 
2.84 
2.79 

2.74 
2.69 
2.62 
2.57 
2.51 

2.46 
2.41 
2.34 
2.24 
2.16 

2.06 
2.01 
1.96 
1.91 
1.83 
1.75 

B.'.'.'.'.'. 
9  

10.. 
11  
12  
13  
14  

15 

16.  ... 
17  
18  
19 

20  
21  
22 

23.... 
24  

25.... 
26  
27  
28  
29  

30.... 
31 

32  
33  
34 

35.  ... 

36  
37 

38  

40.... 
41  

::::::::: 

42  
43 



44 

45  
46  
47 

48  
49  
50  

o  The  Steel  wire  gage  is  the  same  gage  which  has  been  known  by  the  various  names:  "Washbum  & 
Moen  "  "Roebling,"  and  "American  Steel  &  Wire  Go's."    Its  abbreviation  should  be  written   'Stl.  W.  G. 

to  distinguish  it  from  "S.  W.  G.,"  the  usual  abbreviation  for  the  (Bntish)  Standard  wire  gage. 

<>  The  millimeter  diameters  given  for  the  American  wire  gage  were  obtained  by  multiplying  by  25.4001 
the  mathematically  correct  values  in  inches  before  the  latter  were  rounded  off  in  the  fourth  decimal  place 
as  shown  in  the  second  column  of  the  table. 


34  Circular  of  the  Bureau  of  Standards 

TABLE  44.— Equivalents  of  Lettered  Sizes  for  Drills  and    Stubs'  Steel  Wire  Gage 


Letter 

Size  of  letter 

Letter 

Size  of  letter 

Letter 

Size  of  letter 

Inch 

mm 

Inch 

mm 

Inch 

mm 

Z.... 
Y  

x 

0.413 
.404 
.397 
.386 
.377 

.368 
.358 
.348 
.339 
.332 

10.49 
10.26 
10.08 
9.80 
9.58 

9.35 
9.09 
8.84 
8.61 
8.43 

Sir.::::::::::::: 

N  
M  
L 

0.323 
.316 
.302 
.295 
.290 

.281 
.277 
.272 
.266 
.261 

8.20 
8.03 
7.67 
7.49 
7.37 

7.14 
7.04 
6.91 
6.76 
6.63 

F.... 
E  
D  
C  
B  
A 

0.257 
.250 
.246 
.242 
.238 
.234 

6.53 
6.35 
6.25 
6.15 
6.05 
5.94 

w.... 

V  

u 

K.... 
T 

T 

S  
R  
Q  

r::::::::::::::: 

H  
G  

TABLE  45.— Numbered  Sizes,  1  to  60,  for  Drills  and  Stubs'  Steel  Wire  Gage 


Gage  No. 

Stubs'  steelwire 
gage 

Drill  gage  a 

Gage  No. 

Stubs'  steelwire 
gage 

Drill  gage  « 

Inch 

mm 

Inch 

mm 

Inch 

mm 

Inch 

mm 

1... 
2  

0.227 
.219 
.212 
.207 

.204 
.201 
.199 
.197 
.194 

.191 
.188 
.185 
.182 
.180 

,178 
.175 
.172 
.168 

5.766 
5.563 
5.385 
5.258 

5.182 
5.  105 
5.055 
5.004 
4.928 

4.851 

4.775 
4.699 
4.623 
4.572 

4.521 
4.445 
4.369 
4.267 

0.  2280 
.2210 
.2130 
.2090 

.2055 
.2040 
.2010 
.1990 
.1960 

.1935 
.1910 
.1890 
.1850 
.1820 

.1800 
.1770 
.1730 
.1695 

5.791 

5.613 
5.410 
5.309 

5.220 
5.182 
5.105 
5.  055 
4.978 

4.915 
4.851 
4.801 
4.699 
4.623 

4.572 
4.496 
4.394 
4.305 

30... 
31  
32 

0.127 
.120 
.115 
.112 
.110 

.108 
.106 
.103 
.101 
.099 

.097 
.095 
.092 
.088 
.085 

.081 
.079 
.077 
.075 
.072 

.069 
.066 
.063 
.058 
.055 

.050 
.045 
.042 
.041 
.040 
.039 

3.226 
3.048 
2.921 
2.845 
2.794 

2.743 
2.692 
2.616 
2.565 
2.515 

2.464 
2.413 
2.337 
2.235 
2.159 

2.057 
2.007 
1.956 
1.905 
1.829 

1.753 
1.676 
1.600 
1.473 
1.397 

1.270 
1.143 
1.067 
1.041 
1.016 
0.991 

0.  1285 
.1200 
.1160 
.1130 
.1110 

.1100 
.1065 
.1040 
.1015 
.0995 

.0980 
.0960 
.0935 
.0890 
.0860 

.0820 
.0810 
.0785 
.0760 
.0730 

.0700 
.0670 
.0635 
.0595 
.0550 

.0520 
.0465 
.0430 
.0420 
.0410 
.0400 

3.264 

3.048 
2.946 
2.870 
2.819 

2.794 
2.705 
2.642 
2.578 
2.527 

2.489 
2.438 
2.375 
2.261 
2.184 

2.083 
2.057 
1.994 
1.930 
1.854 

1.778 
1.702 
1.613 
1.511 
1.397 

1.321 
1.181 
1.092 
1.067 
1.041 
1.016 

3..., 
4  

5... 

33..  . 
34  

35..  . 
36  
37  
38  
39  

40..  .. 
41  
42  
43  
44  

45  
46  
47 

6  
7  
8  
9 

10.... 
11 

12... 
13  
14  

15.... 
16  
17 

18 

19  
20 

.164 

.161 
.157 
.155 
.153 
.151 

.148 
.146 
.143 
.139 
.134 

4.166 

4.089 

3.988 
3.937 
3.886 
3.835 

3.759 
3.708 
3.632 
3.531 
3.404 

.1660 

.1610 

.1590 
.1570 
.1540 
.1520 

.1495 
.1470 
.1440 
.1405 
.1360 

4.216 

4.089 
4.039 
3.988 
3.912 
3.861 

3.797 
3.734 
3.658 
3.569 
3.454 

48  
49  

50..  ., 
51  
52  
53  
54  

55     . 

21... 
22  
23  
24 

25... 
26  
27 

56  
57  
58  
59  
60  

28  
29  

0  For  sizes  i  to  60  the  dimensions  for  both  drill  gages — Standard  Tool  and  "various  manufacturers" — 
are  identical,  but  differ  from  the  Stubs'  steel  wire  gage. 


Jewelers'  Weights  and  Measures  35 

TABLE  46.— Numbered  Sizes,  60  to  80,  for  Drills  and  Stubs'  Steel  Wire  Gage 


Gage  No. 

Stubs'  steel 
wire  gage 

Standard  Tool  Co. 
drill  gage 

Various  manu- 
facturers 

Inch 

mm 

Inch 

mm 

Inch 

mm 

60  
60^  
61  
62  
63  
64 

0.039 

"'.'038 
.037 
.036 
.035 

.033 
.032 
.031 
.030 

'".'629' 

0.991 

'".'%5' 
.940 
.914 
.889 

.838 
.813 
.787 
.762 

"'.'737' 

0.  0400 
.0390 
.0380 
.0370 
.0360 
.0350 

.0330 

.0320 
.0310 
.0300 
.  02925 
.0290 
.0280 

.0270 

.0260 
.0250 
.0240 
.0230 
.0225 
.0220 
.0210 

.0200 
.0180 
.0160 
.0150 
.0145 
.0140 
.0135 
.0130 

1.016 
.991 
.965 
.940 
.914 
.889 

.838 
.813 
.787 
.762 
.743 
.737 
.711 

.686 
660 

iess 

.610 
.584 
.572 
.559 
.533 

.508 
.457 
.406 
.381 
.368 
.356 
.343 
.330 

0.0400 

'".'6396" 
.0380 
.0370 
.0360 

.0350 
.0330 
.0320 
.0310 

'".'62925' 

.0280 
.0260 

'".6256" 
.0240 

'".'6225" 

.0210 

.0200 
.0180 
.0160 

1.016 

".'99i 
.965 
.940 
.914 

.889 
.838 
.813 
.787 

".'743 

.711 
.660 

".'635 
.610 

".'572 

.533 
.508 
.457 
.406 

65  
66  
67  
68  

T2:::::: 

69H 

70  
71  
71J-6 

.027 
.026 

.686 
.660 

72  
73  
73^ 

.024 
.023 

.610 
.584 

74  
74H  

75  
76  - 
77  
78  
78V£ 

.022 

.020 
.018 
.016 
.015 

.559 

.508 
.457 
.406 
.381 

79  
79^  
80  

.014 

'".'ois' 

.356 
'".'336' 

.0145 
"".Q\3S" 

.368 
".'343 

TABLE  47.— Index  to  Numbered  Sizes,  60  to  80,  for  Drills  and  Stubs'  Steel  Wire 

Gage 


Diameter  of  drill 

Gage  numbers 

Diameter  of  drill 

Gage  numbers 

Inch 

mm 

Stubs' 
steel 
wire 
gage 

Standard 
Tool  Co. 
drill 
gage 

Various 
manu- 
facturers 

Inch 

mm 

Stubs- 
steel 
wire 
gage 

Standard 
Tool  Co. 
drill 
gage 

Various 
manu- 
facturers 

0.0400 

1.016 

59 

60 

60 

0.0250 

0.635 

71H 

72 

.0390 

.991 

60 

60J4 

61 

.0240 

.610 

72 

72 

73 

.0380 

.965 

61 

61 

62 

.0230 

.584 

73 

73 

.  .  .  _  .  .  . 

.0370 

.940 

62 

62 

63 

.0225 

.572 

73>i 

.0360 

.914 

63 

63 

64 

.0220 

.559 

""74"" 

74 

.0350 

.889 

64 

64 

65 

.0210 

.533 

.......... 

743^ 

75 

.838 

65 

65 

66 

.0200 

.508 

75 

76 

!0320 

.813 

66 

66 

67 

.0180 

.457 

76 

76 

77 

.0310 

.787 

67 

67 

68 

.0160 

.406 

77 

77 

78 

.0300 

.762 

68 

68 

0150 

.381 

78 

78 

.  02925 

.743 

68^ 

""69"" 

.0145 

.368 

...„„... 

78H 

'  '  79  '  '  ' 

.0290 

.737 

69 

69 

.0140 

.356 

79 

0280 

711 

69J4 

.  .  .  „_.  .  .  . 

.0135 

.343 

79H 

.  .^.  .  .  . 

!0270 

.686 

.......... 

70 

.0130 

.330 

80 

80 

.0260 

.660 

71 

71 

•  •  •  -7y  •  •  • 

V.  WATCH  GLASSES 
1.  GAGE  SIZES  FOR  WATCH  GLASSES 

The  systems  upon  which  the  gaging  of  watch  glasses  is  based 
are  in  need  of  revision.  Most  manufacturers  and  dealers  are 
labeling  their  glasses  with  several  sets  of  numbers,  each  set  indi- 


36  Circular  of  the  Bureau  of  Standards 

eating  the  diameter  according  to  some  system  of  gaging,  most  of 
which  are  based  upon  some  subdivision  of  the  ligne.11  The  most 
common  of  these  units  based  upon  the  ligne  is  frequently  referred 
to  as  "sixteenths,"  because  in  this  system  the  fraction  over  an 
integral  number  of  lignes  is  expressed  in  sixteenths.  Some  of 
these  labels  include  systems  of  gaging  which  are  practically,  if 
not  entirely,  obsolete.  On  the  other  hand,  several  manufacturers 
use  the  metric  system,  the  unit  for  diameters  being  the  tenth- 
millimeter. 

2.  REASONS  FOR  ADOPTION  OF  METRIC  GAGE  SIZES 

The  metric  system  of  gaging  is  recommended  for  use  in  prefer- 
ence to  the  ligne  and  its  division  into  sixteenths,  for  the  following 
reasons : 

(a)  The  step,  or  change  in  diameter,  between  consecutive  sizes 

in  the  tenth-millimeter  system  is  less  than  the  corresponding  steps 

for  glasses  gaged  by  lignes  and  "sixteenths,"  thereby  making  it 

possible  to  secure  a  better  fit  in  placing  a  glass  into  a  watchcase. 

(6)  Many  watch  glasses  are  manufactured  in  metric  sizes  and 

are  sold  in  ligne  sizes  to  satisfy  the  habits  of  the  retail  trade  in  the 

United  States.     On  the  continent  of  Europe  metric  sizes  are  used. 

(c)  The  ligne  as  a  unit  of  length  is  obsolete  except  in  a  few 

industries,  and  among  them  it  is  falling  into  disuse;  the  millimeter 

is  universal  in  most  commercial  countries. 

3.  SPECIMEN  LABELS 

In  Fig.  2  there  are  shown  two  sample  labels  of  watch  glasses 
giving   the   diameters  in  tenth-millimeters  and  in 
lignes  (frequently  spoken  of  as  sixteenths) ;  the  last 
number  given  on  each  of  these  labels  indicates  by 
gage  number  the  free  height  under  the  center  of  the 
glass  to  the  plane  formed  by  the  circumference  or  rim. 
FIG.  2.— sped-     (See  Table  49,  p.   37).     The   basis   by  which   the 
men  watch     height  of  a  watch  glass  is  gaged  is  that  a  flat  glass 
glass  labels       js  gage  NO   IOj  an(j  that  for  each  unit  distance  of  0.4 
millimeter  in  height,  the  gage  number  decreases  by  unity. 

This  system  of  labeling  is  recommended  by  the  Bureau  of  Stand- 
ards as  the  most  satisfactory  for  the  present,  at  least  so  long  as 
the  ligne  sizes  are  used  in  appreciable  quantities.  The  manufac- 
turers would  prefer  that  metric  sizes  be  used  exclusively,  but  it 
depends  largely  upon  the  retail  establishments  to  simplify  existing 
conditions. 

11  The  origin  of  the  ligne  is  from  the  old,  now  practically  obsolete,  French  toise  (fathom)  as  follows: 
12  lignes=l  pouce,  12  pouce=l  pied,  6  pied=l  toise.  The  relation  between  the  toise  and  meter  is 
1  toise=  1.949090  meters.  (Guillaume,  ''  Unites  et  fitalons,"  page  64.) 


Jewelers'  Weights  and  Measures  37 

4.  INFLUENCE  OF  WATCHCASE  DESIGN 

The  number  of  sizes  of  watch  glasses  which  it  is  necessary  for 
retail  establishments  to  carry  in  stock  is  almost  appalling.  In  the 
table  of  diameters  given  below  (Table  48),  there  are  272  sizes 
shown,  which  apply  to  each  of  the  various  models.  The  Bureau 
desires  to  suggest  that  the  number  of  necessary  sizes  can  be 
eventually  reduced  about  50  per  cent  if  watchcase  manufacturers 
would  confine  themselves  to  the  manufacture  of  cases  requiring 
only  glasses  whose  sizes  are  an  integral  number  of  millimeters ;  to 
provide  for  odd  sizes  resulting  from  inaccurate  workmanship, 
there  would  be  supplied  about  two  tenth-millimeter  sizes  below 
and  above  each  integral  or  whole  millimeter  size. 

5.  CONVERSION  TABLES 

Table  48  is  a  conversion  table  for  the  reduction  of  diameters 
expressed  in  lignes  into  tenth-millimeter  sizes.  Table  49  gives 
the  height  of  glasses  in  both  millimeters  and  inches. 

TABLE  48.— Diameter    of  Watch   Glasses Conversion  of  Lignes    (16ths)    into 

Tenth-millimeters 

[lligne=  2.2559  mm] 


Size 

0 
16 

16 

2 
16 

3 
16 

4 
16 

5 
F6 

6 
16 

A 

8 
16 

9 

16 

10 
16 

11 
16 

16 

13 
16 

14 
16 

15 
16 

6  

135 

137 

138 

140 

141 

142 

144 

145 

147 

148 

149 

151 

152 

154 

155 

157 

7  

158 

159 

161 

162 

164 

165 

166 

168 

169 

171 

172 

173 

175 

176 

178 

179 

8  

180 

182 

183 

185 

186 

188 

189 

190 

192 

193 

195 

196 

197 

199 

200 

202 

9  

203 

204 

206 

207 

209 

210 

211 

213 

214 

216 

217 

219 

220 

221 

223 

224 

10  

226 

227 

228 

230 

231 

233 

234 

235 

237 

238 

240 

241 

243 

244 

245 

247 

11  

248 

250 

251 

252 

254 

255 

257 

258 

259 

261 

262 

264 

265 

266 

268 

269 

12  

271 

272 

274 

275 

276 

278 

279 

281 

282 

283 

285 

286 

288 

289 

290 

292 

13...:  

293 

295 

296 

297 

299 

300 

302 

303 

305 

306 

307 

309 

310 

312 

313 

314 

14  

316 

317 

319 

320 

321 

323 

324 

326 

327 

329 

330 

331 

333 

334 

336 

337 

15  

338 

340 

341 

343 

344 

345 

347 

348 

350 

351 

352 

354 

355 

357 

358 

360 

16  

361 

362 

364 

365 

367 

368 

369 

371 

372 

374 

375 

376 

378 

379 

381 

382 

17  

384 

385 

386 

388 

389 

391 

392 

393 

395 

396 

398 

399 

400 

402 

403 

405 

18  

406 

407 

409 

410 

412 

413 

415 

416 

417 

419 

420 

422 

423 

424 

426 

427 

19  

429 

430 

431 

433 

434 

436 

437 

438 

440 

441 

443 

444 

446 

447 

448 

450 

20  

451 

453 

454 

455 

457 

458 

460 

461 

462 

464 

465 

467 

468 

470 

471 

472 

21  

474 

475 

477 

478 

479 

481 

482 

484 

485 

486 

488 

489 

491 

492 

493 

495 

22 

496 

498 

499 

501 

502 

503 

505 

506 

508 

509 

510 

512 

513 

515 

516 

517 

TABLE  49.— Height  of  Watch  Glasses 


Gage  No. 

Height 

Gage  No. 

Height 

TTITH 

Inch 

mm 

Inch 

10 

0.0 
.4 
.8 
1.2 
1.6 
2.0 

0.000 
.016 
.031 
.047 
.063 
.079 

I  4  

2.4 
2.8 
3.2 
3.6 
4.0 

0.094 
.110 
.126 
.142 

.157 

9  
8  
7  
6  
5  

1  3  
2  

1 

o 

Circular  of  the  Bureau  of  Standards 


VI.  SIZES  OF  WATCHES 

Watch  sizes  are  based  upon  the  diameter  of  the  pillar  plate. 
Watch  movements  made  on  the  continent  of  Europe  have  their 
diameters  expressed  either  in  millimeters  or  in  lignes,  the  former 
method  being  somewhat  uncommon.  A  watch  movement  made  in 
the  United  States  has  its  diameter  expressed  in  terms  of  a  certain 
"Size  No."  The  diameter  of  the  o-size  watch  is  i  5/3oths  of  an 
inch;  the  size  number  increases  for  each  3oth  of  an  inch.  The 
diameter  of  a  i2-size  watch  movement  is  therefore  47/3oths  of 
an  inch  (1.567  inches,  or  39.79  millimeters). 

From  the  third  column  of  Table  50  it  is  seen  that  an  iS-ligne 
watch  equals  almost  exactly  a  i3-size  and  that  a  i5-ligne  equals 
very  closely  a  5 -size.  In  connection  with  the  most  common 
sizes  it  is  well  to  note  that  the  diameter  of  a  i6-size  watch  is 
nearest  to  19  lignes,  12 -size  to  18  lignes,  and  o-size  to  13  lignes. 

TABLE  50.— Watch  Sizes 

[Based  upon  the  diameter  of    pillar  plate.    1   ligne=  2.2559  millimeters;    1   inch=  25.40005  millimeters, 
Size  No.=  Number  of  thirtieths  (30th's)  of  an  inch  in  excess  of  35  thirtieths  (35/30)  of  an  inch] 


Watch 
size 
No. 

.Pillar  plate  diameter 

Watch 
size 
No. 

Pillar  plate  diameter 

Lignes 

mm 

Inches 

SOth's 
of  an 
inch 

Lignes 

irm 

Inches 

SOth's 
of  an 
inch 

32 

56.73 
56.40 
55.88 
55.03 
54.19 

54.14 
53.34 
52.49 
51.89 
51.65 

50.80 
49.95 
49.63 
49.11 
48.26 

47.41 
47.37 
46.57 
45.72 
45.12 

44.87 
44.03 
43.18 
42.86 
42.33 

41.49 
40.64 
40.61 
39.79 
38.95 

38.35 
38.10 
37.25 

2.233 

2.220 
2.200 
2.167 
2.133 

2.132 
2.  100 
2.067 
2.043 
2.033 

2.000 
1.967 
1.954 
1.933 
1.900 

1.867 
1.865 
1.833 
1.800 
1.776 

1.767 
1.733 
1.700 
1.687 
1.667 

1.633 

1.600 
1.599 
1.567 
1.533 

1.510 
1.500 
1.467 

67 

"66  ' 
65 
64 

'"es"' 

62 

'"ei"' 

60 
59 

'"ss"' 

57 
56 

8 

'is  

36.41 
36.09 

35.56 
34.71 
33.87 
33.84 
33.02 

32.17 
31.58 
31.33 
30.48 
29.63 

29.33 

28.79 
27.94 
27.09 
27.07 

26.25 
25.40 
24.81 
24.55 
23.71 

23.69 
22.86 
22.56 
22.01 
21.43 

20.30 
19.  18 
18.05 
16.92 
15.79 
13.54 

.433 
.421 

400 
367 
333 
332 
300 

267 
243 
233 
200 
167 

155 
133 
100 
067 
066 

1.033 
1.000 
.977 
.967 
.933 

.933 
.900 
.888 
.867 
.844 

.799 
.755 
.711 
.666 
.622 
.533 

43 

42 
41 
40 

'"39"' 
38 

"'37 
36 
35 

'"34"' 
33 
32 

31 
30 

'"29  " 
28 

'"27"' 
"'26 

25  

31 
30 
29 

7 
6 
5 

"is".'  

24    

28 
27 

4 
3 

26 

25 
24 

'"23  " 
22 

21 

2 
1 
0 

22  

13.. 

2/0 
3/0 
4/0 

'  i2 

21 

20 
19 

55 

54 

53 
52 
51 

'"56"' 

49 
48 

46 

5/0 
6/0  . 

ii  .'.  

20    . 

18 
17 
16 

7/6 
8/0 

'  '  9/6'  '  ' 

19    .. 

15 

14 
13 

is  

10   

10/0 

9 

12 
11 

8               "         . 

17      .... 

714 

10 
9 

45 

44 

7     •;;  :: 

6 

Jewelers'  Weights  and  Measures  39 

VII.  RING  SIZES 
1.  ORIGINAL  STANDARD 

The  gages  for  finger  rings  that  are  in  use  in  the  United  States 
are  almost  universally  of  the  cone  type,  and  are  designated  by 
two  trade  names.  One  is  "F.  E.  Allen's";  the  other  is  "U.  S. 
Standard. ' '  Apparently  the  principle  of  a  metal  cone  with  gradua- 
tions from  i  to  13  or  o  to  13  is  the  same  on  the  two  gages,  the  only 
apparent  difference  between  the  two  being  in  the  shape  of  the 
wooden  handles.  All  attempts  to  find  any  printed  statement  as 
to  what  the  dimensions  of  the  various  sizes  are  supposed  to  be, 
have  been  unsuccessful.  The  earliest  known  patent  on  the  conical 
ring  gage  was  obtained  by  F.  H.  Allen  on  February  3,  1874,  U.  S. 
Patent  No.  146974.  In  this  patent  there  is  described  quite  accu- 
rately the  conical  gage  with  sizes  i  to  13,  and  quarter  sizes,  as  is 
used  to-day;  there  is  also  described  the  auxiliary  scale  on  the  side 
for  showing  the  circumference  for  each  of  the  various  sizes.  The 
dimensions  of  the  sizes  are  not  stated. 

2.  INTRODUCTION  OF  ERRORS 

From  the  accurate  description  of  the  present  gage  in  Allen's 
patent,  it  may  be  presumed,  perhaps  erroneously  although  prob- 
ably correctly,  that  the  scale  of  sizes  now  in  use  was  well  known 
and  in  use  at  that  time.  There  probably  also  is  little  doubt  but 
that  the  present  gage  sizes  have  descended  from  those  in  use  at  that 
time,  but  by  what  steps  and  intermediary  process  it  is  impossible  to 
state.  Differences  in  the  sizes  have  likely  been  introduced  by  the 
adoption  of  a  common  commercial  copy  as  a  pattern  or  standard. 
In  fact,  a  standard  was  once  obtained  in  this  manner.  A  manu- 
facturing company  in  1917  wrote  to  the  Bureau  of  Standards 
stating  that  they  had  been  making  these  gages  for  nearly  25  years 
and  that  "our  standard  was  probably  obtained  from  a  commercial 
Allen  ring  gage  and  there  appears  to  be  considerable  variations  in 
the  ring  gages  on  the  market.'" 

3.  MANY  SIMILAR  STANDARDS 

While  there  apparently  is  only  one  standard  in  use  in  the  United 
States,  in  reality,  because  of  the  lack  of  specific  dimensions  and 
because  of  the  errors  introduced  by  the  adoption  of  a  common 
commercial  article  as  a  pattern,  there  are  many,  although  similar, 
standards.  One  establishment  recently  purchased  a  considerable 
number  of  platinum  blank  rings  from  a  certain  well-known  and 
highly  advertised  manufacturer.  The  ring  blanks  as  delivered 


4O  Circular  of  the  Bureau  of  Standards 

tested  out  about  one-quarter  size  smaller  than  the  size  ordered, 
and  as  can  be  readily  understood,  there  is  no  means  of  recourse 
even  though  there  had  been  a  desire  on  the  part  of  the  purchaser 
to  obtain  it.  From  the  gages  examined  in  a  few  retail  establish- 
ments in  the,  same  city,  there  were  discovered  differences  corre- 
sponding to  about  a  third  of  a  size.  Continued  search  in  other 
cities  may  be  expected  to  disclose  much  larger  differences.  Letters 
from  one  important  manufacturer  of  ring  gages  state  that  the 
diameters  they  use  corresponding  to  sizes  i  and  13  are  0.485  and 
0.877  inch,  respectively;  from  another,  they  are  0.491  and  0.877 
inch,  respectively.  On  the  other  hand,  measurements  obtained 
during  one  afternoon  for  gages  in  use  in  retail  houses  in  one  locality 
gave  a  range  of  values  for  size  i  from  0.480  to  0.491  inch,  and  for 
size  13  from  0.870  to  0.878  inch. 

4.  CONFUSION  ALSO  IN  USE  OF  GAGE 

Not  only  is  there  confusion  in  the  ring  sizes  and  standards  but 
confusion  also  exists  in  the  method  of  use  of  the  gages.  Some 
companies  bring  the  top  of  the  ring  to  the  mark  on  the  gage, 
others  use  the  middle  of  the  ring,  while  still  others  use  the  lower 
edge  of  the  ring.  These  differences  in  the  method  of  use  are 
equivalent  for  broad  rings  to  an  appreciable  part  of  a  size,  and 
serve  to  increase  the  differences  between  the  various  standards. 
The  differences  between  the  various  gages  for  any  one  size  are 
somewhat  small  in  comparison  with  the  latitude  permissible  in 
the  retail  trade,  but  for  the  jobbers  and  manufacturers  it  seems 
desirable,  however,  that  the  diameter  used  for  each  of  the  various 
sizes  and  the  method  of  use  of  the  gage  should  be  identical. 

5.  OUTLINE  OF  THE  PROBLEM 

The  figures  given  in  the  preceding  paragraphs  show  approxi- 
mately the  dimensions  of  the  gages  in  use  as  compared  with  those 
of  the  standards  of  two  ring  gage  manufacturers.  The  Bureau  of 
Standards  intends  to  take  up  this  problem  by  obtaining  more  com- 
plete information  as  to  the  dimensions  of  gages  in  different  parts 
of  the  country,  and  with  the  cooperation  of  those  fundamentally 
interested  in  this  problem,  it  hopes  to  be  able  to  select  some  values 
which  best  represent  the  average  dimensions  of  existing  standards. 


Jewelers'  Weights  and  Measures 

VIII.  MISCELLANEOUS  TABLES 

TABLE  51.— Decimal  Equivalents  of  Gold  Karats  a 

[The  number  oi  karats  indicates  the  number  of  24ths  of  pure  gold  in  an  alloy] 


Number  of  karats 

Pure  gold 

Number  of  karats 

Pure  gold 

IK  
2K  
3K 

Fineness 
0.0417 
0833 
1250 

13  K  ... 
14K  
15  K 

Fineness 
0.  5417 
.5833 
6250 

4K..  . 

1667 

16  K 

.6667 

5K  
6K  
7K 

2083 
2500 
2917 

17K.... 
18  K  
19  K 

.7083 
.7500 
7917 

8K..  . 

20  K 

.8333 

9K  

3750 

21  K  

.8750 

10  K  
UK  
12  K  

4167 
4583 
5000 

22  K  ... 
23K  
24K  

.9167 
.9583 
1.0000 

0  The  spelling  "karat"  is  in  general  use  among  jewelers  to  designate  the  gold  karat  (fineness  of  gold) 
and  is  consistent  with  the  accepted  abbreviation  for  this  term,  "  K";  also,  it  affords  a  distinctive  term 
as  compared  with  "carat,"  which,  abbreviated  by  " c "  designates  a  unit  of  weight  used  in  measuring 
precious  stones. 

TABLE  52.— Densities  a  of  Various  Metals 


Metal 

Density 

Metal 

Density 

Aluminum  
Antimony 

g/cm' 
2.70 
6.618 

Manganese  
Nickel 

g/cm3 
7.42 
8.75 

Bismuth  
Cadmium  
Chromium 
Cobalt  
Copper 

9.781 
8.648 
6.92 
8.71 
8.89 

Osmium  
Palladium  
Platinum  
Rhodium  
Silver 

22.5 
12.16 
21.37 
12.44 
10.48 

Gold  ... 
Iridium          
Iron  
Lead 

19.33 
22.42 
7.86 
11.342 

Tantalum  
Tin  
Tungsten  
Zinc 

16.6 
7.29 
18.8 
7.10 

'  The  values  in  this  table  are  taken  from  "Smithsonian  Physical  Tables,"  7th  revised  edition,  p.  no. 

TABLE  53.— Melting  Points  o  Of  Various  Metals  & 


Metal 

Melting  point 

Melting  point 

Metal 

Melting  point 

Melting  point 

Mercury  
Tin 

°C 

-  38.87 
+231.9 

«F 

-  37.97 
+449.  4 

Manganese  
Nickel 

°C 

1230 
1452 

OF 

2246 
2646 

Bismuth  

271 
320  9  * 

520 
609  6 

Cobalt  

1480 
1530 

2696 
2786 

Lead  
Zinc 

327.4 
419.4 

621.3 
786.9 

Palladium  
Chromium             

1550 
1615 

2822 
2939 

Antimony  

630.0 
658  7 

1166.0 
1217  7 

Platinum  
Rhodium 

1755 
1950 

3191 
3542 

Radium 

700 

1292 

Iridium  

2350(?) 

4260 

Silver  
Gold  
Copper  

960.5 
1063.0 
1083.  0 

1760.9 
1945.  5 
1981.  4 

Osmium  
Tantalum  
Tungsten  

2700(?) 
2900 
3400 

4890 
5250 
6152 

o  At  high  temperatures  some  of  the  values  are  somewhat  uncertain.     Temperatures    centigrade  are 
rounded  off,  and  the  exact  Fahrenheit  equivalents  are  usually  given. 

6  This  table  is  taken  from  B.  S.  Circular  No.  35,  4th  edition  (revision  of 
melting  points  for  all  of  the  elements. 


Dec.  1,  1919),  which  gives  the 


42  Circular  of  the  Bureau  of  Standards 

TABLE  54. — Conversion  of  Centigrade  Temperatures  (C)  into  Fahrenheit 
Temperatures  (F) 

[Temperature  Fahrenheit=  9  5  temperature  centigrade  +32] 


°c 

OF 

°C 

°F 

°C 

°F 

—40 

—  40 

60 

140 

200 

392 

-35 

-  31 

65 

149 

300 

572 

-30 

-  22 

70 

158 

400 

752 

-25 

-  13 

75 

167 

500 

932 

—20 

-  4 

80 

176 

600 

1112 

-15 

+  5 

85 

185 

700 

1292 

-10 

14 

90 

194 

800 

1472 

-  5 

23 

95 

203 

900 

1652 

Zero 

32 

100 

212 

1000 

1832 

+  5 

41 

105 

221 

1100 

2012 

10 

50 

110 

230 

1200 

2192 

15 

59 

115 

239 

1300 

2372 

20 

68 

120 

248 

1400 

2552 

25 

77 

125 

257 

1500 

273L 

30 

86 

130 

266 

1600 

2912 

35 

95 

135 

275 

1700 

3092 

40 

104 

140 

284 

1800 

3272 

45 

113 

145 

293 

1900 

3452 

50 

122 

150 

302 

2000 

3632 

55 

131 

155 

311 

2500 

4532 

TABLE  55. — Conversion  of  Fahrenheit  Temperatures  (F)  into  Centigrade 
Temperatures  (C) 

[Temperature  centigrade-  5/9  (temperature  Fahrenheit  -32)] 


°F 

°C 

°F 

°C 

°F 

0  C 

°F 

°C 

—40 

—40.0 

60 

15.6 

165 

73.9 

500 

260.0 

-35 

-37.2 

65 

18.3 

170 

76.7 

600 

315.6 

-30 

-34.4 

70 

21.1 

175 

79.4 

700 

371.1 

—25 

-31.7 

75 

23.9 

180 

82.2 

800 

426.7 

-20 

-28.9 

80 

26.7 

185 

85.0 

900 

482.2 

-15 

-26.1 

85 

29.4 

190 

87.8 

1000 

537.8 

-10 

-23.3 

90 

32.2 

195 

90.6 

1100 

593.3 

-  5 

-20.6 

95 

35.0 

200 

93.3 

1200 

648.9 

Zero 

-17.8 

100 

37.8 

205 

96.1 

1300 

704.4 

+  5 

-15.0 

105 

40.6 

210 

98.9 

1400 

760.0 

10 

-12.2 

110 

43.3 

212 

100.0 

1500 

815.6 

15 

-  9.4 

115 

46.1 

215 

101.7 

1600 

871.1 

20 

-  6.7 

120 

48.9 

220 

104.4 

1700 

926.7 

25 

-  3.9 

125 

51.7 

225 

107.2 

1800 

982.2 

30 

-  1.1 

130 

54.4 

230 

110.0 

1900 

1037.  8 

32 

Zero 

135 

57.2 

235 

112.8 

2000 

1093.3 

35 

+  1-7 

140 

60.0 

240 

115.6 

2500 

1371.  1 

40 

4.4 

145 

62.8 

245 

f!8.3 

3000 

1648.  9 

45 

7.2 

150 

65.6 

250 

121.1 

3500 

1926.  7 

50 

10.0 

155 

68.3 

300 

148.9 

4000 

2204.4 

55 

12.8 

160 

71.  1 

400 

204.4 

4500 

2482.  2 

Jewelers'  Weights  and  Measures 


43 


Degrees 
Fahrenheit 


£300 


£200 


Degrees 
Centigrade 

KOO 


I30O 


—       12- OO  White 


I9OO 


1800 


1.    APPROXIMATE    TEMPER- 
ATURES  BY  COLOR 


The  estimation  of  tem- 
perature by  the  color  of  a 
hot  body  is  influenced  by 
so  many  factors   that   it 
is    attended    with    great 
uncertainties.     The  chart       I7O° 
shown    in    Fig.    3,    taken 
from  Bullens'  "Steel  and      I60° 
Its    Heat   Treatment," 
page  369,  is  appended  as      isoo 
a    rough   guide   for   such 
temperature  estimation. 


1300 


(ZOO 


1100 


IOOO 


9OO 


BOO 


Light   Yellow 

I0°°  Lemon 

Orange 
9OO     Salmon 

Bright    Red 


8OO 


700 


600 


5OO 


Cherry    or  Pull   Red 

Medium   Cherry 
Dark    Cherry 

Blood    Red 
Faint    Red 


FlG.  3. — Temperature  and  color  of  hot  body 


INDEX 


[For  analytical  outline  see  "Contents,"  p.  3.] 


Abbreviations u,  12, 

principles 

Acre 

American  Steel  and  Wire  Co.'s  wire  gage 

American  wire  gage 8: 

Apothecaries'  units  (see  also  under  the  name 

of  each  unit) 

Are 

Area,  units 

tables 

Avoirdupois  units  of  mass  (see  also  under  the 

name  of  each  unit) 


Barrel  (for  dry  commodities) 

Birmingham  wire  gage 

Board  foot 

(British)  Standard  wire  gage 

Brown  &  Sharpe  wire  gage 

Bushel... 


Capacity,  tables 

units 

Carat,  metric 

metric,  new,  adoption 

old,  in  use  in  United  States  previous  to 

July  i,  1913 27 

Centare 

Centi-  (prefix) 

Centigrade  temperatures 

Centigram 

Centiliter 

Centimeter 7, 

Centimeter  and  inch,  chart  showing  relative 

values  of 

Centimeter,  cubic 9, 

square 

Chain 

square 

Color,  approximate  temperatures  by  use 

Contents,  table 

Cord 

Cubic  measure,  units  (see  also  under  the  name 

of  each  unit) 

Deci-  (prefix) 

Decigram 

Deciliter 

Decimeter 

cubic 

square 

Deka-  (prefix) 

Dekagram 

Dekaliter 

Dekameter 

cubic 

Densities  of  metals 

Douzieme . .  , 


Page. 

Page. 

,  13)  14 

Douzieme  caliper  

32 

10 

Dram,  apothecaries'  

14 

12 

avoirdupois  

14 

30,33 

fluid  

13,21 

5,30,33 

Drill  gages  31.  34,35 

Dry  units  of  capacity  (see  also  under  the  name 

14 

of  each  unit)  

13 

12 

II 

Fahrenheit  temperatures  

42,43 

20 

Fathom 

1 

Finger  rings  sizes 

14,22 

Firkin 

' 

Fluid  units  (see  also  under  the  name  of  each 

13 

13 

unit) 

31,33 

Foot 

ii  I  - 

beard  

12 

31,33 

cubic  

12,  2O 

,30,33 

square  

12,20 

13 

Fractions,  common  (binary),  of  inch,  conver- 

sion into  millimeters  

IS 

21 

Fundamental  relationships  of  metric  system. 

9 

13 

,  28,  29 

Furlong  

II 

6 

Gages  (see  also  Wire  gages;  Drill  gages;  and 

Plate  gage)  

29 

,  28,  29 

Gallon   British  imperial 

21 

12 

United  States                                                9, 

I 

8 

Gill 

'-a 

42,43 

Gold  karat  (fineness  of  gold)  

41 

14 

Grain  9.10.14 

22,23 

13 

,11,15 

Gram  9,  10,  14,  22,  23,  24,  25 

* 

Hand  

II 

Hectare  

12 

,  12,20 

Hecto-  (prefix)  

8 

12,20 

Hectogram  

14 

11 

Hectoliter  

13 

12 

Hectometer  

ii 

43 

cubic  

12 

3 

Hot  body,  approximate  temperature,  by  use 

12 

of  color 

43 

14 

12,20 

Imperial  wire  gage  , 

31 

8 

Inch  9,  10,  n,  15, 

16,18 

14 

cubic  9, 

12,20 

13 

12,  2O 

ii 

Introduction  

6 

12 

12 

Karats,  gold,  decimal  equivalents  

41 

8 

Kilo-  (prefix)  

8 

14 

Kilogram  7,  9,  14, 

22,26 

13 

Kilometer  

7," 

II 

cubic  

12 

12 

square  

12 

41 

32 

Length  conversion  tables  15,  16,  17, 

18,19 

45 


46 


INDEX 


Page. 

Length,  units  of n 

Ligne 32,36,37,38 

Link ii 

square 12 

Liquid  units  (see  also  under  the  name  of  each 

unit) i3>  21 

Liter 7,8,9,13,20,21 

Liter,  distinction  between,  and  1000  cubic 

centimeters 8,9 

"Manufacturers'  standard"  drill  gage 31, 34, 35 

Mass  (weight) 9, 14, 22, 33, 24, 25, 26 

tables 22, 23, 24, 25, 26 

units 14 

Melting  points  of  metals 41 

Metal,  density 41 

melting  points 41 

Meter 7,9,  xi,  15 

cubic 12, 20 

square 11,20 

Metric  carat.    See  Carat,  metric. 

Metric  system 7 

fundamental  relationships 9 

general  outline 7 

legal  status 7 

units  of xi 

Use  in  medical  work  of  War  Department. . .         6 
Metric  ton.    See  Ton,  metric. 

Metric  units,  subdivisions 8 

spelling  and  abbreviations 10 

Micron. 8,11,19 

Mil ii 

Mile,  geographical ii 

nautical  (sea) ii 

square 12 

statute ii 

Milli-  (prefix) 8 

Milligram 7, 9, 14, 27, 28, 29 

Milliliter 7,8, 13, 21 

Millimeter 7, 8, 10,  n,  15, 18 

cubic 12 

square 12 

Minim 13.21 


Old  English  or  London  wire  gage. . . 
Ounce,  apothecaries' 

avoirdupois 

fluid 

troy , 


31 
14 

.  ..  14,22 
...  13,21 
14,  22, 25 


Peck 13 

Pennyweight 10, 14, 22, 24 

Pint,  dry 13 

liquid 13, 21 

Plate  gage,  United  States  standard 29 


Point 

Pound,  apothecaries' 

avoirdupois 

troy 


Page. 
11,16,32 


Quart,  dry. 
liquid . . . . 


13 
9,13,21 


Rings,  ringer,  sizes 39 

Rod n 

square ia 

Roebling  wire  gage 30,33 

Scruple,  apothecaries' 14 

Sizes  of  watches 38 

Span ix 

Spelling  of  metric  units 10 

Square  (see  also  under  the  name  of  each  unit) 

1 1 , 12, 20 

Standard  Tool  Co.'s  drill  gage 31,34,35 

Standard  wire  gage 31,33 

Steel  wire  gage 30,33 

Store ia 

Stubs'  steel  wire  gage 30,31, 33, 34,35 

Stubs'  wire  gage 33 

Subdivisions  of  metric  units 8 


Tables,  use 

Temperatures  by  color  of  hot  body . 

Toise 

Ton,  long 

metric 

short 

Troy,  ounce 


9, 10, 27 
43 


14 

•    7)14,22 

. ..   14,22 

14, 22, 25 


Use  of  tables 9,  ">,  27 

United  States  standard  plate  gage 29 

"Various  manufacturers'"  drill  gage 31,34,35 

Volume,  tables 20 

units 12 

Washburn  &  Moen  wire  gage 30, 33 

Watch  glasses,  gage  sizes 35,37 

height 36,37 

labels 36 

Watchcase  design,  influence  upon  sizes  of 

watch  glasses 36 

Watches,  size 38 

Weight,  tables  (see  also  Mass) 22, 23, 24, 25, 26 

units 14 

Wire  gages 29,30 

tabular  comparison 33 

Yard ii,  15 

cubic 12, 20 

square ix,  20 


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